Aplicación del láser de helio-neón en pacientes con melasma facial / Use of helium-neon laser in patients with melasma: en

Introducción: El melasma facial consiste en una hiperpigmentación que se origina por un incremento de la melanina epidérmica o dérmica, o ambas, y se localiza en las áreas fotoexpuestas, lo cual afecta, en ocasiones, la autoestima de hombres y mujeres. Objetivo: Evaluar la efectividad del tratamiento con láser de helio-neón en pacientes con melasma facial. Métodos: Se realizó un estudio cuasiexperimental de intervención terapéutica en 34 pacientes con diagnóstico clínico y dermatoscópico de melasma facial, atendidos en la consulta de dermatología del Hospital General Docente Dr. Juan Bruno Zayas Alfonso en Santiago de Cuba, de enero del 2019 a igual mes del 2020, para lo cual se conformaron dos grupos: uno de estudio, que recibió tratamiento con láser, y el otro de control, tratado con crema de hidroquinona a 2 %. La información fue procesada y resumida en valores absolutos y porcentaje; asimismo, se utilizó la prueba paramétrica de homogeneidad de la Χ2, con un nivel de significación α=0,05. Resultados: En general, la mayoría de los pacientes correspondieron al grupo etario de 39-48 años (35,3 %) y al sexo femenino (82,3 %), tenían color de la piel mestizo (76,5 %) y lesiones de tamaño mediano (58,8 %). Si bien no existieron diferencias estadísticamente significativas entre las respuestas terapéuticas de cada grupo de estudio, en los pacientes tratados con láser de helio-neón la mejoría clínica fue evidente a los 3 meses de finalizada la intervención (70,6 %). Conclusiones: El tratamiento con láser de helio-neón fue efectivo en los pacientes con melasma.

Introduction: Melasma is a hyperpigmentation caused by an increase in epidermal or dermal melanin concentration, or both, and it is located on photoexposed cutaneous regions. It affects sometimes men's and women's self-esteem. Objective: To evaluate the effectiveness of helium-neon laser treatment in patients with melasma. Methods: A quasi-experimental study of therapeutic intervention in 34 patients with clinical and dermoscopic diagnosis of melasma, who were assisted at the Dermatology Service of Dr. Juan Bruno Zayas Alfonso Teaching General Hospital in Santiago de Cuba was carried out from January, 2019, to the same month in 2020, for which two groups were formed: the study group, that received laser treatment, and the control group, treated with 2% hydroquinone cream. The information was processed and expressed in absolute values and percentage; likewise, the Χ2 test for homogeneity was used, with a significance level of α=0.05. Results: In general, most of the patients belonged to 39-48 age group (35.3%) and were female (82.3%), with mixed skin color (76.5%) and medium-sized lesions (58.8%). Although there were no statistically significant differences between the therapeutic responses of each study group, clinical improvement in patients treated with helium-neon laser was evident 3 months post-intervention (70.6%). Conclusions: Helium-neon laser treatment was effective in patients with melasma.

Role of DNMT3a in Hydroquinone-Induced Hematopoietic Stem Cell Toxicity / 中国实验血液学杂志

OBJECTIVE@#To investigate the regulatory effect and mechanism of DNA methyltransferase 3A (DNMT3a) in hydroquinone-induced hematopoietic stem cell toxicity.@*METHODS@#Cells (HSPC-1) were divided into 4 groups, that is A: normal HSPC-1; B: HQ-intervented HSPC-1; C: group B + pcDNA3 empty vector; D: group B + pcDNA3- DNMT3a. RT-qPCR and Western blot were used to detect the expression levels of DNMT3a and PARP-1 mRNA and protein, respectively. Cell morphology was observe; Cell viability and apoptosis rate of HSPC-1 were detected by MTT and flow cytometry, respectively.@*RESULTS@#Compared with group A, the expression levels of DNMT3a mRNA and protein in HSPC-1 of group B were decreased, while PARP-1 mRNA and protein were increased (P<0.05); there was no significant difference in the above indexes between group C and group B; compared with group B, the expression levels of DNMT3a mRNA and protein showed increased, while PARP-1 mRNA and protein were decreased significantly in cells of group D transfected with DNMT3a (P<0.05). Cells in each group were transfected with DNMT3a and cultured for 24 h, HSPC-1 in group A showed high density growth and mononuclear fusion growth, while the number of HSPC-1 in group B and C decreased and grew slowly. Compared with group B and C, the cell growth rate of group D was accelerated. The MTT analysis showed that cell viability of HSPC-1 in group B were lower than that of group A at 24 h, 48 h and 72 h (P<0.05); after transfected with DNMT3a, the cell viability of HSPC-1 in group D were higher than that of group B at 24 h, 48 h and 72 h (P<0.05). The apoptosis rate of cells in group B was significantly higher than that of group A (P<0.001), while the apoptosis rate in group D was lower than that of group B (P<0.001).@*CONCLUSION@#DNMT3a may be involved in the damage of hematopoietic stem cells induced by hydroquinone, which may be related to the regulation of PARP-1 activity by hydroquinone-inhibited DNMT3a.

PARP-1 participates in regulation of cell cycle signaling in the hydroquinone-induced TK6 malignant transformation / 中国职业医学

@#To investigate the expression of polyadenosine diphospho-ribose polymerase 1 (PARP-1) and p16/ retinoblastoma (Rb) protein in hydroquinone (HQ)-induced TK6 cells and their regulatory mechanisms. Methods According to the 2×2 factorial design model, TK6 cells were divided into PBS-TK6 group and HQ-TK6 group based on HQ exposure, and then sub-divided into non-DOX intervention subgroup and DOX intervention subgroup based on DOX intervention, a total of four groups. The PBS-TK6 group was treated with phosphate buffer saline, and the HQ-TK6 group was treated with HQ at a final concentration of 20.0 μmol/L. The non-DOX intervention subgroup was added with 0.05% dimethyl sulfoxide; and the DOX intervention subgroup was added with PARP-1 agonist DOX at a final concentration of 0.5 μmol/L. The distribution of cell cycle was detected by flow cytometry. The protein expression of p16/Rb, cyclin D1 (cyclinD1), multifunctional protein E2 transcription factor 1 (E2F1), Rb, and p-Rb were detected by Western blot, and the level of p16 ribosylation was detected by immunofluorescence and immunoprecipitation. Results Compared with the PBS-TK6 group, the cell cycle distribution percentage in G0/G1 phase and the relative expression levels of p16 proteins were decreased in the cells of the HQ-TK6 group (all P<0.05). The cell cycle distribution percentage in S phase and the relative expression levels of cyclinD1 and p-Rb proteins were up-regulated (all P<0.05). Compared with the non-DOX intervention group, the cell cycle distribution percentage in G0/G1 and G2/M phases and the relative expression level of p16 protein increased in the DOX intervention group (all P<0.05). The percentage of cells in S phase and the relative expression levels of cyclinD1 and p-Rb proteins were down-regulated (all P< 0.05). The results of interaction effect analysis showed that compared with the non-DOX PBS-TK6 cells, the relative expression levels of Rb and E2F1 protein in the DOX PBS-TK6 cells intervention group were down-regulated (all P<0.05). The relative expression level of Rb protein in non-DOX HQ-TK6 cell group was down-regulated (P<0.05), and the relative expression of E2F1 protein was up-regulated (P<0.05). Compared with DOX PBS-TK6 cell group, the relative expression level of Rb protein in DOX HQ-TK6 cell group was down-regulated and that of E2F1 protein was up-regulated (all P<0.05). Compared with the non-DOX HQ-TK6 cell group, the relative expression level of Rb protein in the DOX HQ-TK6 cell group was up-regulated and that of E2F1 protein was down-regulated (all P<0.05). Conclusion PARP-1 participates in cell cycle regulation by regulating the p16/Rb signaling pathway in TK6 cells.

A case report on hydroquinone induced exogenous ochronosis

Exogenous ochronosis is an infrequent skin disorder characterised by bluish-black or grayish brown pigmentation on dermis. It is the most common condition caused due to long term application of Hydroquinone skin preparations for melasma, skin brightening, cholasma, acne induced pigmentation etc. This report refers to a case of 39-year-old female patient who presented to the hospital with chief complaints of progressive formation of dark lesions over face, neck since one and half-year. She had history of usage of hydroquinone (4%) cream for skin brightening for a period of three months. Based on clinical findings and history she was diagnosed to have acquired exogenous ochronosis and was treated with microdermabrasion, cosmelan peel, yellow peel, glutathione tablets, topical sunscreen and kojic acid cream. Patient noted 50% improvement in her condition after 4 months of treatment. It is believed that application of high concentrations of hydroquinone for a prolonged period causes exogenous ochronosis. This case report suggests that exogenous ochronosis can occur after three months of application.

Antioxidative effect and mechanism of tert-butyl hydroquinone on rat retinal Müller cells under high glucose condition / 中华实验眼科杂志

Objective@#To expore the impact of teniary butyl hydroquinone (tBHQ) on Müller cells in SD rats retina under high glucose condition, and discuss the mechanism of tBHQ.@*Methods@#The Müller cells of SD rats were cultured in vitro and the experiment was divided into normal control group, high glucose group and tBHQ intervention group.Western blot and quantitative real time PCR were used to determine the expression of nuclear factor erythroid 2-related factor 2 (Nrf2), hemeoxygenase-1 (HO-1), hypoxia inducible factor-1α (HIF-1α) and vascular endothelial growth factor (VEGF) protein and mRNA in each group.@*Results@#Müller cells cultured in vitro were flat with irregularly sharp.The nucleus was oval, while the cytoplasm was abundant.Adjacent cells were interwoven to a network.Western blot assay showed the overall expression of Nrf2, HO-1, HIF-1α, and VEGF in Müller cells of normal control group, high glucose group, and tBHQ intervention group were significantly different (F=73.831, 148.618, 152.269, 91.217, all at P<0.001); Among them, the relative expressions of Nrf2, HO-1, HIF-1α and VEGF proteins in the high glucose group were 0.17±0.02, 0.47±0.02, 0.67±0.07, and 0.6±0.05, which were increased in comparion with 0.06±0.01, 0.19±0.03, 0.06±0.00 and 0.07±0.02 in the normal control group, with statistically significant differences (t=4.114, 9.275, 16.479, 13.353, all at P<0.001); the relative expressions of Nrf2 and HO-1 proteins in the tBHQ intervention group were 0.40±0.06 and 0.72±0.05, which were increased by comparion with those in the higher glucose group, with statistically significant differences (t=7.847, 7.947, both at P<0.001); the relative expressions of HIF-1α and VEGF proteins in the tBHQ intervention group were 0.18±0.04, 0.26±0.07, which were decreased in comparion with those in the higher glucose group, but were increased in comparion with those in normal control group, with statistically significant differences (t=13.215, 8.444, both at P<0.001). Quantitative real time PCR showed that the relative mRNA expressions of Nrf2, HO-1, HIF-1α, and VEGF in Müller cells of normal control group, high glucose group, and tBHQ intervention group were significantly different (F=340.317, 1 582.911, 488.852, 185.699, all at P<0.001); the relative mRNA expressions of Nrf2, HO-1, HIF-1α, and VEGF proteins in the high-glucose group were 1.53±0.06, 1.50±0.04, 2.56±0.09, and 3.04±0.19, which were increased in comparion with 1.07±0.07, 0.95±0.05, 0.99±0.02, and 1.09±0.08 in the normal control group, with statistically significant differences (t=7.292, 15.014, 30.550, 18.573, all at P<0.001); The relative mRNA expressions of Nrf2 and HO-1 proteins in the tBHQ intervention group were 2.68±0.09 and 2.94±0.05, which were increased in comparion with those in the high-glucose group, with statistically significant differences (t=18.046, 39.458, both at P<0.001); The relative mRNA expression of HIF-1α and VEGF protein in the tBHQ intervention group were 1.48±0.05 and 1.6±0.08, which were decreased by comparion with those in the higher glucose group were increased in comparion with those in normal control group, with statistically significant differences (t=21.036, 13.739, both at P<0.001).@*Conclusions@#tBHQ protects Müller cells from damage in high glucose condition by activating anti-oxidative stress signaling pathway of Nrf2/ARE.

Antioxidative effect and mechanism of tert-butyl hydroquinone on rat retinal Müller cells under high glucose condition / 中华实验眼科杂志

Objective To expore the impact of teniary butyl hydroquinone (tBHQ) on Müller cells in SD rats retina under high glucose condition,and discuss the mechanism of tBHQ.Methods The Müller cells of SD rats were cultured in vitro and the experiment was divided into normal control group,high glucose group and tBHQ intervention group.Western blot and quantitative real time PCR were used to determine the expression of nuclear factor erythroid 2-related factor 2 (Nrf2),hemeoxygenase-1 (HO-1),hypoxia inducible factor-1α (HIF-1α) and vascular endothelial growth factor (VEGF) protein and mRNA in each group.Results Müller cells cultured in vitro were flat with irregularly sharp.The nucleus was oval,while the cytoplasm was abundant.Adjacent cells were interwoven to a network.Western blot assay showed the overall expression of Nrf2,HO-1,HIF-1α,and VEGF in Müller cells of normal control group,high glucose group,and tBHQ intervention group were significantly different (F =73.831,148.618,152.269,91.217,all at P＜0.001);Among them,the relative expressions of Nrf2,HO-1,HIF-1α and VEGF proteins in the high glucose group were 0.17±0.02,0.47±0.02,0.67±0.07,and 0.6±0.05,which were increased in comparion with 0.06±0.01,0.19±0.03,0.06±0.00 and 0.07±0.02 in the normal control group,with statistically significant differences (t =4.114,9.275,16.479,13.353,all at P ＜ 0.001);the relative expressions of Nrf2 and HO-1 proteins in the tBHQ intervention group were 0.40±0.06 and 0.72±0.05,which were increased by comparion with those in the higher glucose group,with statistically significant differences (t =7.847,7.947,both at P＜0.001);the relative expressions of HIF-1α and VEGF proteins in the tBHQ intervention group were 0.18±0.04,0.26±0.07,which were decreased in comparion with those in the higher glucose group,but were increased in comparion with those in normal control group,with statistically significant differences (t =13.215,8.444,both at P＜ 0.001).Quantitative real time PCR showed that the relative mRNA expressions of Nrf2,HO-1,HIF-1α,and VEGF in Müller cells of normal control group,high glucose group,and tBHQ intervention group were significantly different (F =340.317,1 582.911,488.852,185.699,all at P＜0.001);the relative mRNA expressions of Nrf2,HO-1,HIF-1α,and VEGF proteins in the high-glucose group were 1.53 ± 0.06,1.50 ± 0.04,2.56 ± 0.09,and 3.04 ± 0.19,which were increased in comparion with 1.07±0.07,0.95±0.05,0.99±0.02,and 1.09±0.08 in the normal control group,with statistically significant differences (t =7.292,15.014,30.550,18.573,all at P ＜ 0.001);The relative mRNA expressions of Nrf2 and HO-1 proteins in the tBHQ intervention group were 2.68±0.09 and 2.94±0.05,which were increased in comparion with those in the high-glucose group,with statistically significant differences (t =18.046,39.458,both at P＜0.001);The relative mRNA expression of HIF-1α and VEGF protein in the tBHQ intervention group were 1.48±0.05 and 1.6±0.08,which were decreased by comparion with those in the higher glucose group were increased in comparion with those in normal control group,with statistically significant differences (t =21.036,13.739,both at P＜0.001).Conclusions tBHQ protects Müller cells from damage in high glucose condition by activating anti-oxidative stress signaling pathway of Nrf2/ARE.

Development And Validation Of Analytical Spectrophotometric And Rp-Hplc Methods For The Simultaneous Estimation Of Hydroquinone, Hydrocortisone And Tretinoin Ternary Mixture In Topical Formulation

Objective: Development and validation of spectrophotometric and RP-HPLC methods for the simultaneous determination of Hydroquinone (HQ), Hydrocortisone (HC) and Tretinoin (TRT) ternary combination in pharmaceutical preparation. Methods: The proposed spectrophotometric method was able to determine TRT directly from its absorption spectrum at 362 nm, however, HQ and HC from their first derivative spectra at 284 nm and 252 nm, respectively, without any separation step. The RP-HPLC method was developed using a C18 Sunfire© waters column with a mobile phase composed of acetonitrile: phosphate buffer (adjusted to pH 6.1 using ortho-phosphoric acid) in the ratio of 30:70 %, v/v, respectively at a flow rate of 0.8 ml/min. Quantification was based on measuring peak areas at 260 nm. Results: The spectrophotometric method was able to selectively quantify each of HQ, HC and TRT in the ranges of 10-50 µg/ml, 2-10 µg/ml and 0.5-5 µg/ml, respectively. The RP-HPLC method was able to produce well-resolved peaks after 3.0, 8.2 and 20.2 min, in the ranges of 2-10 µg/ml, 0.1-1 µg/ml and 0.05-2 µg/ml, for HQ, HC and TRT, respectively. The obtained A, D1 or peak areas values plotted against the concentration of each of the three components showed linear response in the stated ranges. Both methods were validated in terms of linearity, LOD, LOQ, precision, accuracy and selectivity. Conclusion: Both developed proposed methods were applied for the determination of the active ingredients in the pharmaceutical formulation and the common excipients did not interfere in the analysis. The RP-HPLC method proved to be more sensitive when compared to the applied spectrophotometric method. However, the applied spectrophotometric methods, considered as green analytical chemistry, is a simple, time-saving method that requires minimal use of a hazardous solvent.

Efficacy of intense pulsed light combined with hydroquinone cream to treat melisma / 中华医学美学美容杂志

Objective To evaluate the efficacy and safety of intense pulsed light (IPL) combined with hydroquinone cream for melasma treatment.Methods Thirty-five patients with melasma were treated between February 2015 and February 2017,20 patients treated with IPL combined with hydroquinone cream and 15 patients with IPL alone.All cases were female patients with Fitzpatrick skin types Ⅲ and Ⅳ,and subjected to 4 weeks treatment 1 time,5 times for a course of treatment.All patients were followed up for six months and the efficacy and safety of the treatment were analyzed comprehensively by subjective satisfaction and physician evaluation.Results All the patients were treated without discomfort and treated patients were effectively followed up.The satisfactory rate of IPL treatment group was 73.3％,and that of combined with hydroquinone cream group was 100％.Two groups of satisfactory rates were higher in IPL combined with hydroquinone cream.The total effective rate of the IPL treatment group was 53.3％ compared with that of the 35 patients before and after treatment;in IPL combined with hydroquinone cream treatment group the total effective rate was 85.0％.IPL combined with hydroquinone cream treatment group was significantly more effective than the treatment group (P＜0.05).All treatment patients did not present with tissue damage,pigmentation and other adverse reactions.Conclusions IPL combined with hydroquinone cream is a safe and effective treatment of melasma,and patients get a higher rate of satisfaction.

The change of reactive oxygen species and cell cycle in bone marrow cells of mice with benzene-induced aplastic anemia / 中国职业医学

OBJECTIVE: To explore the effect of reactive oxygen species(ROS) and cell cycle in bone marrow cells in benzene-induced aplastic anemia(AA) mouse model. METHODS: Specific pathogens free male CD1 mice were randomly divided into control group and exposure group(n=10, each group). The mice in exposure group were subcutaneously injected with benzene at a dose of 2 mL/kg body weigh diluted 1 ∶1 in corn oil, while the mice in control group were treated with equal volume of corn oil, 3 times a week for a total of 25 times. After exposure, the blood routine and reticulocyte percentage of peripheral blood of mice were examined. The femur histopathology was performed. The levels of benzene and its metabolites hydroquinone, and phenol in blood, liver and bone marrow were tested by solid-phase extraction gas chromatography mass spectrometry. The level of ROS and the changes of cell cycle in bone marrow mononuclear cells(BMMNCs) were determined by flow cytometry. The protein expression of Cyclin D1 and cyclin-dependent kinase 4(CDK4) in BMMNCs was detected by Western blot. RESULTS: Since the 10 th benzene exposure, the body mass of mice in the exposure group was lower than that in the control group at the same time point(P<0.05). After the benzene exposure, all the counts of white blood cell, red blood cell, platelet, and hemoglobin level and reticulocyte percentage in peripheral blood of mice in the exposure group were decreased when compared with the control group(P<0.05). Bone marrow histopathological examination showed that bone marrow hematopoietic cells were decreased and non-hematopoietic cells were increased in the exposure group. In this study, a mouse model of AA induced by benzene was successfully established. The levels of benzene, hydroquinone and phenol in exposure group increased in blood, liver, and bone marrow compared to control group(P<0.05). Furthermore, the level of benzene from high to low were blood, liver and bone marrow, while the levels of hydroquinone and phenol were mainly stored in the blood and bone marrow in exposure group. Compared with the control group, the level of ROS, S phase fraction, and the relative protein expression of Cyclin D1 and CDK4 in BMMNCs increased, while the G1 phase fraction decreased in exposure group(P<0.01). CONCLUSION: The results suggest that benzene and its metabolites induce an increase of ROS level and S phase cell arrest, that play an important role in the pathogenesis and development of benzene-induced AA.

Influência da Hidroquinona nas respostas imune humoral e celular induzida por vacina viral com proteína recombinante (Dengue) / The Influence of Hydroquinone in the humoral and cellular immune responses elicited by vaccination with Dengue envelope recombinant Protein

A fumaça do cigarro apresenta mais de 8700 substâncias identificadas, as quais já foram relacionadas com o desenvolvimento das mais variadas doenças. Dentre elas, uma substância relevante neste contexto de toxicidade do cigarro é a hidroquinona (HQ), gerada após a biotransformação do benzeno inalado. A HQ apresenta atividades relacionadas com a imunossupressão das respostas imune inata e adaptativa, observados mais no contexto in vitro e parcamente no in vivo; contudo, nenhum estudo ainda trouxe a abordagem do efeito da exposição à HQ sobre a resposta induzida por vacinação. Sendo assim, será que a exposição à fumaça do cigarro ou à HQ influenciaria na resposta de células B e geração de anticorpos induzidas por imunizações com vacinas anti-virais? Observamos que, após a exposição diária com 2500 ppm de HQ (equivalente a um maço de cigarro fumado / dia) por 8 semanas e vacinação com proteína recombinante codificadora do domínio III do Envelope do vírus da Dengue sorotipo 2 (EDIII) mais o adjuvante Alum, houve uma "tendência" para menores títulos de IgG total e IgG1 específicos à EDIII em camundongos C57BL/6. Análises histológicas revelaram um menor número de folículos e redução significativa de suas áreas no baço do grupo HQ em comparação com os não expostos. Para entendermos o efeito da HQ sobre a resposta humoral, realizamos uma análise de dados públicos de transcriptoma obtidas de amostras de sangue de humanos. Curiosamente, observamos que a HQ regula positivamente genes relacionados com a ativação de células B, assim como a migração e quimiotaxia de neutrófilos e outros leucócitos. Como é sabido que existe uma população de neutrófilos (N2) com a capacidade de auxiliar as respostas de células B, hipotetizamos que essas células poderiam disparar um mecanismo imunocompensatório que aumenta os títulos de anticorpos no grupo HQ

The cigarette smoke has more than 8700 harmful substances related to the occurrence of the most varied diseases. Among them, a relevant substance is the hydroquinone (HQ), generated upon the biotransformation of inhaled benzene. In vitro and in vivo analyses have demonstrated that HQ can suppress both innate and adaptive immune responses. However, no study has approached the effect of the HQ exposure on the vaccination-induced response. Thus, would the exposure to the cigarette smoke or HQ influence the B-cell and antibody responses elicited by immunizations with antiviral vaccines? We observed a "tendency" to lower titers of IgG total and IgG1 anti-EDIII in mice daily exposed to 2,500 ppm of HQ for 8 weeks and vaccinated. Histological analyses revealed a smaller number of follicles and a significant reduction in their area in the HQ group in comparison to their counterparts. In order to understand the effect of the HQ on the humoral response, we performed an analysis of public transcriptome data derived from human blood samples. We observed that the HQ up-regulates the expression of genes related to B cell activation as well as the migration and chemotaxis of neutrophils and other leukocytes. Considering that N2 neutrophils have the ability to help the B cell response, we have hypothesized that the HQ exposure may trigger an immunocompensatory effect, increasing the humoral response

Differential proteomics analysis on hydroquinone-induced cytotoxicity in TK6 cells / 中国职业医学

OBJECTIVE: To study the effect of hydroquinone on the protein expression on human lymphoblastoid cell TK6,and to explore the molecular mechanism of hydroquinone-induced cellular response. METHODS: The TK6 cells were treated with 20. 0 μmol/L of hydroquinone for 24. 0 hours. Total protein was extracted by protein lysis buffer and quantified. The proteins were separated by two-dimensional gel electroporthressis. After image analysis,the difference in electrophoresis was selected for enzymatic hydrolysis. The mass spectrometry identification was performed using matrix-assisted laser desorption ionization tandem time-of-flight mass spectrometry. The TK6 cells were treated with hydroquinone at a concentration of 0. 0,5. 0,10. 0 and 20. 0 μmol/L for 24. 0 hours,and total protein was extracted. The expression of heat shock protein 70( HSP70) and ubiquitin-binding enzyme 2( UBE2N) of which were identified by mass spectrometry were assayed by western blot. RESULTS: A total of 48 differential expression protein spots were detected after hydroquinone treatment,and the mass spectrometry identified 30 differentially expressed proteins with up-or down-regulation. These proteins were related to oxidative stress,mitochondrial energy metabolism,cytoskeleton,cell cycle,DNA damage repair,and so on. The relative expression levels of HSP70 and UBE2 N in TK6 cells of 5. 0,10. 0,20. 0 μmol/L hydroquinone group were higher than those of 0. 0 μmol/L hydroquinone group( P < 0. 05),which was consistent with the mass spectrometry results. CONCLUSION: Hydroquinone can induce cytotoxicity in TK6 cells through oxidative stress,which induces the change of mitochondrial energy metabolism and DNA damage repair.

Hidroquinona: vilã ou heroína? / Hydroquinone: hero or villain?

A hidroquinona é usada como agente clareador há mais de 50 anos, e, nos últimos 20, suas segurança e toxicidade têm sido questionadas. Nesta revisão bibliográfica, pode-se verificar que seu potencial carcinogênico e mutagênico não foi comprovado até hoje em humanos. Além disso, estamos muito mais expostos à hidroquinona do que imaginamos, tanto em compostos cosméticos (por exemplo, tinturas de cabelos) quanto em alimentos, como a pera, bebidas e o café. Portanto, sua prescrição como despigmentante em concentrações de até 4% é segura e sem consequências sistêmicas.

Hydroquinone has been used as a whitening agent for more than 50 years, however its safety and toxicity have been questioned in the last two decades. In the present literature review, it is possible to verify that its carcinogenic and mutagenic potential in humans has not been proven to date. In addition, the population is in fact much more exposed to hydroquinone than commonly perceived, via both cosmetic compounds (e.g. hair dyes) and foods (e.g. pear, beverages and coffee). Therefore, prescribing hydroquinone as a depigmenting agent in concentrations of up to 4% is safe and devoid of systemic consequences.

Protective effect of Bu Shen Yang Xue Ming Mu Formula on oxidative injury in ARPE-19 cells / 国际眼科杂志(Guoji Yanke Zazhi)

AIM: To explore the effect of Bu Shen Yang Xue Ming Mu (BSYXMM) Formula on hydroquinone-induced oxidative stress injury in ARPE-19 cells.METHODS: The oxidative injury model of ARPE-19 cell was induced by exposure to various concentrations of hydroquinone (HQ) to determine the optimal concentration.Intestinal absorption solutions of BSYXMM Formula were prepared.Effect of intestinal absorption solutions of BSYXMM Formula on the cell viability was detected by CCK-8 assay,and the percentage of apoptotic cells was measured by TUNEL assay.The levels of superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) in ARPE-19 cells were detected by means of chemical colorimetry.RESULTS: It was found that ARPE-19 cell viability significantly decreased when the concentration of HQ was higher than 90μmol/L.Compared with the model group,1% and 2% intestinal absorption solutions in the pre-treatment group could significantly alleviate HQ-induced injury (P<0.01) and 0.5% and 5% intestinal absorption solutions in the pre-treatment group could alleviate the injury in certain degree(P<0.05).While in the treatment group 1% and 2% intestinal absorption solutions could alleviate the injury to some extent (P<0.05).TUNEL results showed that the apoptosis rate decreased significantly in the pre-treatment group (P<0.01)and to some extent in the treatment group (P<0.05)compared with the model group.It was shown that both levels of SOD and GSH-Px in pre-treatment group and treatment group were markedly higher than that of model group(P<0.05),and pre-treatment group had more significant effect (P<0.01,P<0.05).CONCLUSION: BSYXMM Formula could protect against HQ-induced oxidative stress injury in ARPE-19 cells,which may be related with the increasing of antioxidant enzyme in the cells.

Effects of miR-7-5p on TK6 cell damage induced by hydroquinone / 中国职业医学

OBJECTIVE: To investigate the mechanism of miR-7-5p in TK6 cell damage induced by hydroquinone( HQ) by constructing stable miR-7-5p over-expressing human lymphoblastoid TK6 cell line using lentivirus. METHODS: i) The miR-7-5p over-expression lentivirus vectors were constructed,and then infected to TK6 cells. The miR-7-5p overexpression stable TK6 cell line( TK6-miR-7-5p cells) and negative control cells( TK6-NC cells) were selected with puromycin. The infection efficiency was confirmed by real-time fluorescent quantitative polymerase chain reaction assay.ii) TK6,TK6-NC and TK6-miR-7-5p cells were treated with HQ at final concentrations of 0 and 40 μmol/L for 48 hours.Cell viability was determined by CCK-8 assay. The early apoptosis rate of cells was detected by flow cytometry. The relative expression of poly( ADP-ribose) polymerase-1( PARP-1) and breast cancer susceptibility gene 1( BRCA1) proteins in 3 kinds of cells treated with HQ at the final concentration of 40 μmol/L was detected by Western blotting. RESULTS: i) The TK6 cell line with stable expression of miR-7-5p were successfully screened. Compared with normal TK6 cells,the relative expression of miR-7-5p in TK6-miR-7-5p cells increased by about 17 times( P < 0. 01) with no significant changes in cell morphology. ii) After treatment with 40 μmol/L HQ,the survival rate of TK6-miR-7-5p cells decreased compared with normal TK6 cells and TK6-NC cells( P < 0. 01),early apoptosis rate increased( P < 0. 01),the relative expression of PARP-1 and BRCA1 protein was decreased( P < 0. 05). CONCLUSION: MiR-7-5p may lead to the increase of early apoptosis in TK6 cells induced by HQ through inhibiting the DNA damage repair capacity related to PARP-1 and BRCA1.

Effect of silencing of poly(ADP-ribose) polymerase-1 on cell apoptosis induced by hydroquinone in rat bone marrow mesenchymal stem cells / 中国职业医学

OBJECTIVE: To explore the effect of silencing of poly( ADP-ribose) polymerase-1( PARP-1) on cell apoptosis induced by hydroquinone( HQ) in rat bone marrow-derived mesenchymal stem cells( BMMSCs). METHODS: i) The RNA expression vectors for PARP-1 gene were transfected into BMMSCs. Neomycin was used to select the transfected cells that stably expressed PARP-1-shRNA. Western blotting was used to examine the gene silencing efficiency. ii) BMMSCs with PARP-1 silencing were sorted as the treated group,while BMMSCs with empty vector were considered as the control group.HQ dissolved in phosphate buffer solution at the concentrations of 0. 0,2. 5,5. 0,10. 0,20. 0,40. 0,80. 0,160. 0 and320. 0 μmol / L were given to both groups for 24 hours. The cell viability was detected by methyl thiazolyl tetrazolium assay,and the concentration of HQ was chosen for the following study based on cell viability. iii) Both groups were treated by HQ at concentrations of 0. 0-20. 0 μmol / L for 24 hours,then the apoptosis of BMMSCs was detected by flow cytometry. The PARP-1 mRNA expression was determined by real-time fluorescent quantitative polymerase chain reaction assay. RESULTS: i) PARP-1 silencing cells and empty vector control cells were successfully screened with a mass concentration of 400 mg / L neomycin,and confirmed by level of protein expression. The interference efficiency of PARP-1 gene and inhibition efficiency was 85. 00%. ii) Based on the result of cell viability,HQ at concentrations of 0. 0-20. 0 μmol / L was chosen for the following study. iii) Compared with the group treated by HQ at concentration of 0. 0 μmol / L,the rate of early apoptosis of control group increased significantly with HQ at concentration of 10. 0 μmol / L while that of treated group was increased significantly at concentration of 5. 0 μmol / L( P < 0. 05). In addition,at concentrations of 0. 0-10. 0 μmol / L,the rates of early apoptosis in both groups increased in a dose-dependent manner( P < 0. 01). Compared with the group treated by HQ at concentrations of 0. 0 μmol / L,the expression of PARP-1 mRNA of both groups increased significantly at the concentration of 5. 0 μmol / L( P < 0. 05). The expression of PARP-1 mRNA of treated group was less than that of control group with HQ at every concentration( P < 0. 05). At concentrations of 0. 0-20. 0 μmol / L,the expression of PARP-1 mRNA of both groups increased in a dose-dependent manner( P < 0. 01). CONCLUSION: Silencing PARP-1 in BMMSCs caused cell apoptosis. PARP-1 may participate in cell apoptosis induced by HQ.

Increased Skin Irritation by Hydroquinone and Rsetinoic Acid Used in Combination

BACKGROUND: Hydroquinone (HQ) is frequently combined with retinoic acid (RA) to enhance lightening efficacy, which may also affect skin irritancy. Although skin irritation leads to postinflammatory hyperpigmentation, little research has been performed to compare skin irritancy between each component and the combination. OBJECTIVE: This study was done to examine whether HQ-RA combination increased skin irritation induced by HQ or RA alone. METHODS: Patch testing was performed using maximum therapeutic and higher concentrations of HQ and RA in 10 volunteers, and then, it was performed using their popular therapeutic concentrations and combination in the other 20 volunteers. In vitro irritation was also assessed in primary cultured normal human keratinocytes treated with 80% and 50% cell survival doses of HQ, 80% cell survival dose of RA, and their combination. RESULTS: The combination in patch testing induced stronger erythema than the corresponding concentrations of HQ and RA, which was remarkable with use of combination of higher concentrations. In cultured keratinocytes, the RA combination significantly decreased cell viability, but increased cytotoxicity and extracellular interleukin 1 alpha release with corresponding doses of HQ. CONCLUSION: The results of patch tests and in vitro irritation assessment tests suggested that HQ and RA increased skin irritation when used in combination.

Hydroquinone suppresses IFN-β expression by targeting AKT/IRF3 pathway

Previous studies have demonstrated the role of hydroquinone (HQ), a hydroxylated benzene metabolite, in modulating various immune responses; however, its role in macrophage-mediated inflammatory responses is not fully understood. In this study, the role of HQ in inflammatory responses and the underlying molecular mechanism were explored in macrophages. HQ down-regulated the expression of interferon (IFN)-β mRNA in LPS-stimulated RAW264.7 cells without any cytotoxicity and suppressed interferon regulatory factor (IRF)-3-mediated luciferase activity induced by TIR-domain-containing adapter-inducing interferon-β (TRIF) and TANK-binding kinase 1 (TBK1). A mechanism study revealed that HQ inhibited IRF-3 phosphorylation induced by lipopolysaccharide (LPS), TRIF, and AKT by suppressing phosphorylation of AKT, an upstream kinase of the IRF-3 signaling pathway. IRF-3 phosphorylation is highly induced by wild-type AKT and poorly induced by an AKT mutant, AKT C310A, which is mutated at an inhibitory target site of HQ. We also showed that HQ inhibited IRF-3 phosphorylation by targeting all three AKT isoforms (AKT1, AKT2, and AKT3) in RAW264.7 cells and suppressed IRF-3-mediated luciferase activities induced by AKT in HEK293 cells. Taken together, these results strongly suggest that HQ inhibits the production of a type I IFN, IFN-β, by targeting AKTs in the IRF-3 signaling pathway during macrophage-mediated inflammation.

Protecting effects and mechanism of tert-butyl hydroquinone on retinal cells in type 2 diabetic rats / 中华实验眼科杂志

Background Apoptosis is a primary clinical pathological mechanism of diabetic retinopathy (DR).Oxidative stress and high glucose can activate cell apoptosis pathway and thus leads to cellular damage.It is confirmed that tert-butyl hydroquinone (tBHQ) plays an antioxidation effect,however,whether it has a protective role on retinal cells in DR is still unelucidated.Objective This study was to investigate the effect of tBHQ on vascular endothelial growth factor (VEGF) and bcl-2 expressions in retina of type 2 diabetic rats and its possible mechanism via nuclear factor erythroid 2-related factor 2/antioxidant response element (Nrf2/ARE) signal pathway.Methods Fifty clean healthy male SD rats were included in this experimental study.Ten rats were fed with normal diet as the normal control group,and other rats were fed with high fatty and high sugar food for 4 weeks.After 12 hours of fasting,streptozotoin (STZ) (30 mg/kg) was intraperitoneally injected to induce the type 2 diabetic models.The model rats were randomly divided into the diabetic control group and tBHQ group and 1％ tBHQ was added into the high fatty and sugar food 1 week after modeling in the tBHQ group.Fasting plasma glucose (FPG) level,blood total cholesterol (TC) level,blood triglyceride (TG) level,high density lipoprotein-cholesterol (HDL-C),low density lipoproteincholesterol (LDL-C) and fasting serum insulin (FINs) were detected 4 and 12 weeks after modeling,respectively,and radio immunoassay was used to detect the FIN levels of the rats.The relative expression of VEGF and bcl-2 in retinas of the rats were assayed by immunohistochemistry and fluorescence real-time quantitative PCR (qRT-PCR).The use of the animals complied with the Regulations for the Administration of Affairs Concerning Experimental Animals by State and Technology Commission.Results Type 2 diabetic models were successfully established in 35 rats with successful rate 92.1％.The FIN levels were significantly different among different groups and time points (Fgroup =22.480,P =0.000;Ftime =7.636,P =0.008).The FPG,TC,TG and LDL-C levels were significantly different among the groups (FPG:Fgroup =78.531,P =0.000;TC:Fgroup =28.049,P =0.000;TG:Fgroup =13.108,P =0.000;LDL-C:Fgroup =6.804,P＜0.05).Immunohistochemistry showed that VEGF and bcl-2 were mainly expressed in retinal ganglion cell layer,inner plexiform layer and outer plexiform layer.The expressions of VEGF and bcl-2 proteins were significantly different among different groups (VEGF:Fgroup =11.805,P =0.000;bcl-2:Fgroup =22.943,P =0.000);the expression level of bcl-2 protein was higher in 12 weeks after modeling than that in 4 weeks after modeling in the tBHQ group (P＜0.05).The expressions of VEGF and Bcl-2 mRNA in rat retinas were significantly different among different groups and time points (VEGF:Fgroup =79.220,P =0.000;Ftimo =6.090,P＜0.05;Bcl-2:Fgroup =105.000,P=0.000;Ftime =13.170,P=0.001).Four and eight weeks after modeling,the expressions of VEGF and Bcl-2 mRNA in the diabetic control group and tBHQ group were significantly higher than that in the normal control group,and the expressions of Bcl-2 mRNA in the tBHQ group were significantly higher than that in the model control group (all at P＜0.05);the expression of Bcl-2 mRNA was higher at 12 weeks after modeling than that at 4 weeks in the tBHQ group (P＜0.05).Conclusions tBHQ produces anti-oxidative-damage and anti-apoptosis effects on retinal cells by up-regulating VEGF expression and down-regulating bcl-2 expression in DR rats.In addition,tBHQ may have effects on lowering high blood sugar,regulating insulin and blood lipid levels.

Determinación de hidroquinona usando un electrodo de carbono vítreo modificado con quitosano, nanotubos de carbono de pared múltiple y líquido iónico. Posible uso como sensor / Determination of hydroquinone using a glassy carbon electrode modified with chitosan, multi-wall carbon nano-tubes and ionic liquid. Possible use as sensor

La propiedad electroactiva de hidroquinona (HQ) se estudió sobre un electrodo de carbono vítreo modificado con quitosano, nanotubos de carbono de pared múltiple (Ch-MWCNT-GCE). La HQ se depositó a un potencial controlado sobre la superficie del electrodo y la oxidación de la HQ se midió por voltametría de onda cuadrada (SWV, por sus siglas en inglés). Se observó una corriente de oxidación a 0,39 V y una corriente de reducción a 0,21 V con un ΔV de 0,18 V; ello indicó un proceso reversible. Un aumento en las corrientes de oxidación y de reducción de casi 50% se observó cuando el Ch-MWCNT-GCE se recubrió con líquido iónico (LI). El electrodo se caracterizó por voltamperometría cíclica (CV, por sus siglas en inglés) en presencia y sin la presencia de diferentes líquidos iónicos con distinto anión, siendo el más óptimo el líquido iónico (LI) 1-butil-3-metilimidazolio hexafluorofosfato (BMIMPF6). Se estudiaron las variables experimentales como pH, tiempo de adsorción (t ads) y potencial de adsorción (Eads), así como también las potenciales interferencias. Bajo las óptimas condiciones (pH 3,0; t acc 60s; Eacc 0,10 V), el pico de la corriente es proporcional a la concentración de HQ entre 4,20 * 10-6 y 30,0 * 10-6 mol L-1, con un límite de detección de 2,45 * 10-7 mol L-1. La desviación estándar relativa para una solución que contiene 1,0 * 10-4 mol L-1 de HQ, fue de 1,5% para siete medidas iguales. El método se validó con una muestra de agua dopada con HQ.

Property of the electroactive hydroquinone (HQ) was studied on a glassy carbon electrode modified chitosan, multi wall carbon nanotubes (Ch-MWCNT-GCE). HQ is deposited at a controlled potential to the electrode surface and oxidation of HQ is measured by square wave voltammetry (SWV). An oxidation current to 0.39 V and a reduction current to 0.21 V with a 0.18 ΔV indicating a reversible process were observed. An increase in the flow of oxidation and reduction of almost 50% was observed when the Ch-MWCNT-GCE was coated with ionic liquid (LI). The electrode was characterized by cyclic voltammetry (CV) in the presence and without the presence of different ionic liquids with different anion being the most optimal ionic liquid (LI) 1-butyl-3-methyllimidazolio hexafluorophosphate (BMIMPF6). Experimental variables such as pH, adsorption time (TADs) and adsorption potential (Eads), as well as potential interference, were studied. Under optimal conditions (pH 3.0; t acc 60s; Eacc 0.10 V) the peak current is proportional to the concentration of HQ between 4.20 * 10-6 and 30.0 * 10-5 mol L-1 with a detection limit of 2.45 * 10-7 mol L-1. The relative standard deviation for a solution containing 1.0 * 10-4 mol L-1 HQ was 1.5% for seven equal measures. The method was validated with a water sample doped with HQ.

El impacto de la hidroquinona usada como un modelo de efector redox sobre la desnitrificación potencial, la actividad microbiana y las condiciones redox de un suelo cultivable / Impact of hydroquinone used as a redox effector model on potential denitrification, microbial activity and redox condition of a cultivable soil

In this microcosm study, we analyzed the effect produced by hydroquinone on the expression of soil biological denitrification, in relation to the redox state of the soil, both in terms of intensity factor (Eh′) and capacity factor (amount of oxidized or reduced compounds). The supplementation of an Argiudoll soil with hydroquinone decreased the soil apparent reduction potential (Eh′) and soil dehydrogenase activity (formazan production from tetrazolium chloride reduction; redox capacity factor), the relationship between both factors being highly significative, r = 0.99 (p < 0.001). The bacterial population (measured by colony forming units) increased, and the production of N2O was greater (p < 0.001) at 200 and 400 μg/g dry soil doses. Furthermore, there was an inverse relationship between soil dehydrogenase activity and the number of bacteria (r = −0.82; p < 0.05), increased denitrification activity and changes in the CO2/N2O ratio value. These results suggest that hydroquinone at supplemented doses modified the soil redox state and the functional structure of the microbial population. Acetate supplementation on soil with hydroquinone, to ensure the availability of an energy source for microbial development, confirmed the tendency of the results obtained with the supplementation of hydroquinone alone. The differences observed at increased doses of hydroquinone might be explained by differences on the hydroquinone redox species between treatments.

En este trabajo estudiamos, en condiciones de microcosmos, el efecto que produce la hidroquinona sobre la expresión de la desnitrificación en relación con el estado de óxido-reducción del suelo, en términos de factor de intensidad (Eh′) y de factor de capacidad (cantidad de compuestos oxidados o reducidos). La suplementación de un suelo argiudol con hidroquinona disminuyó el potencial de reducción aparente (Eh′) y la actividad deshidrogenasa (producción de formazán a partir de la reducción de cloruro de tetrazolio; factor de capacidad redox), la relación entre ambos factores fue altamente significativa, r = 0,99 (p < 0,001). La población bacteriana heterotrófica (medida como unidades formadoras de colonias) aumentó y la producción de N2O fue mayor (p < 0,001) con las dosis de 200 y 400 μg/g de suelo seco. Además se observó una relación inversa entre la producción de formazán y el número de bacterias (r = −0,82; p < 0,05), la actividad desnitrificadora aumentó y se produjeron cambios en el valor del cociente CO2/N2O. Estos resultados sugieren que la hidroquinona, en las dosis empleadas, modificó el estado redox del suelo y la estructura funcional de la población microbiana. La suplementación con acetato en el suelo con hidroquinona, a fin de asegurar la disponibilidad de una fuente de energía para el desarrollo bacteriano, confirmó la tendencia de los resultados obtenidos con la suplementación con hidroquinona solamente. Las diferencias observadas con el incremento en la dosis de hidroquinona podrían explicarse por las diferencias sobre las especies redox de la hidroquinona entre los tratamientos.