PPAR-γ activation promotes xenogenic bioroot regeneration by attenuating the xenograft induced-oxidative stress / 国际口腔科学杂志·英文版

Xenogenic organ transplantation has been considered the most promising strategy in providing possible substitutes with the physiological function of the failing organs as well as solving the problem of insufficient donor sources. However, the xenograft, suffered from immune rejection and ischemia-reperfusion injury (IRI), causes massive reactive oxygen species (ROS) expression and the subsequent cell apoptosis, leading to the xenograft failure. Our previous study found a positive role of PPAR-γ in anti-inflammation through its immunomodulation effects, which inspires us to apply PPAR-γ agonist rosiglitazone (RSG) to address survival issue of xenograft with the potential to eliminate the excessive ROS. In this study, xenogenic bioroot was constructed by wrapping the dental follicle cells (DFC) with porcine extracellular matrix (pECM). The hydrogen peroxide (H2O2)-induced DFC was pretreated with RSG to observe its protection on the damaged biological function. Immunoflourescence staining and transmission electron microscope were used to detect the intracellular ROS level. SD rat orthotopic transplantation model and superoxide dismutase 1 (SOD1) knockout mice subcutaneous transplantation model were applied to explore the regenerative outcome of the xenograft. It showed that RSG pretreatment significantly reduced the adverse effects of H2O2 on DFC with decreased intracellular ROS expression and alleviated mitochondrial damage. In vivo results confirmed RSG administration substantially enhanced the host's antioxidant capacity with reduced osteoclasts formation and increased periodontal ligament-like tissue regeneration efficiency, maximumly maintaining the xenograft function. We considered that RSG preconditioning could preserve the biological properties of the transplanted stem cells under oxidative stress (OS) microenvironment and promote organ regeneration by attenuating the inflammatory reaction and OS injury.

Effect of mitophagy related genes on the antioxidant properties of Saccharomyces cerevisiae / 生物工程学报

Mitophagy is a process whereby cells selectively remove mitochondria through the mechanism of autophagy, which plays an important role in maintaining cellular homeostasis. In order to explore the effect of mitophagy genes on the antioxidant activities of Saccharomyces cerevisiae, mutants with deletion or overexpression of mitophagy genes ATG8, ATG11 and ATG32 were constructed respectively. The results indicated that overexpression of ATG8 and ATG11 genes significantly reduced the intracellular reactive oxygen species (ROS) content upon H2O2 stress for 6 h, which were 61.23% and 46.35% of the initial state, respectively. Notable, overexpression of ATG8 and ATG11 genes significantly increased the mitochondrial membrane potential (MMP) and ATP content, which were helpful to improve the antioxidant activities of the strains. On the other hand, deletion of ATG8, ATG11 and ATG32 caused mitochondrial damage and significantly decreased cell vitality, and caused the imbalance of intracellular ROS. The intracellular ROS content significantly increased to 174.27%, 128.68%, 200.92% of the initial state, respectively, upon H2O2 stress for 6 h. The results showed that ATG8, ATG11 and ATG32 might be potential targets for regulating the antioxidant properties of yeast, providing a new clue for further research.

Oxidative stress induces autophagy to inhibit the proliferation and apoptosis of human bone marrow mesenchymal stem cells (hBMSCs) / 细胞与分子免疫学杂志

Objective To investigate the effect of H2O2-induced oxidative stress on autophagy and apoptosis of human bone marrow mesenchymal stem cells (hBMSCs). Methods hBMSCs were isolated and cultured. The cells were divided into control group, 3-MA group, H2O2 group, H2O2 combined with 3-MA group. DCFH-DA staining was used to analyze the level of reactive oxygen species (ROS). hBMSCs were treated with 0, 50, 100, 200, 400 μmol/L H2O2, and then the cell viability was detected by CCK-8 assay. The level of autophagy was detected by monodansylcadaverine (MDC) staining and LysoTracker Red staining. The cell apoptosis was detected by flow cytometry. Western blotting was used to detect the expression of beclin 1, mTOR, phosphorylated mTOR (p-mTOR), cleaved caspase-3(c-caspase-3) and caspase-3 proteins. Results Compared with the control group and 3-MA group, ROS level and autophagosomes were increased and the proliferation and apoptosis were decreased in H2O2 group. The protein expression of beclin 1, mTOR, c-caspase-3 was up-regulated, while the p-mTOR was down-regulated. Compared with the 3-MA group, the H2O2 combined with 3-MA group also had an increased ROS level and autophagosomes, but not with significantly increased apoptosis rate; The protein expression of beclin 1, mTOR, c-caspase-3 was up-regulated, and the p-mTOR was down-regulated. Conclusion H2O2 can induce hMSCs to trigger oxidative stress response. It enhances the autophagy and inhibits the proliferation and apoptosis of hBMSCs.

Preparation, characterization and biocompatibility of calcium peroxide-loaded polycaprolactone microparticles / 浙江大学学报·医学版

OBJECTIVES@#To explore the physicochemical characteristics and biocompatibility of calcium peroxide (CPO)-loaded polycaprolactone (PCL) microparticle.@*METHODS@#The CPO/PCL particles were prepared. The morphology and elemental distribution of CPO, PCL and CPO/PCL particles were observed with scanning electron microscopy and energy dispersive spectroscopy, respectively. Rat adipose mesenchymal stem cells were isolated and treated with different concentrations (0.10%, 0.25%, 0.50%, 1.00%) of CPO or CPO/PCL particles. The mesenchymal stem cells were cultured in normal media or osteogenic differentiation media under the hypoxia/normoxia conditions, and the amount of released O2 and H2O2 after CPO/PCL treatment were detected. The gene expressions of alkaline phosphatase (ALP), Runt-associated transcription factor 2 (RUNX2), osteopontin (OPN) and osteocalcin (OCN) were detected by realtime RT-PCR. SD rats were subcutaneously injected with 1.00% CPO/PCL particles and the pathological changes and infiltration of immune cells were observed with HE staining and immunohistochemistry at day 7 and day 14 after injection.@*RESULTS@#Scanning electron microscope showed that CPO particles had a polygonal structure, PCL particles were in a small spherical plastic particle state, and CPO/PCL particles had a block-like crystal structure. Energy dispersive spectroscopy revealed that PCL particles showed no calcium mapping, while CPO/PCL particles showed obvious and uniform calcium mapping. The concentrations of O2 and H2O2 released by CPO/PCL particles were lower than those of CPO group, and the oxygen release time was longer. The expressions of Alp, Runx2, Ocn and Opn increased with the higher content of CPO/PCL particles under hypoxia in osteogenic differentiation culture and normal culture, and the induction was more obvious under osteogenic differentiation conditions (all P<0.05). HE staining results showed that the muscle tissue fibers around the injection site were scattered and disorderly distributed, with varying sizes and thicknesses at day 7 after particle injection. Significant vascular congestion, widened gaps, mild interstitial congestion, local edema, inflammatory cell infiltration, and large area vacuolization were observed in some tissues of rats. At day 14 after microparticle injection, the muscle tissue around the injection site and the tissue fibers at the microparticle implantation site were arranged neatly, and the gap size was not thickened, the vascular congestion, local inflammatory cell infiltration, and vacuolization were significantly improved compared with those at day 7. The immunohistochemical staining results showed that the expressions of CD3 and CD68 positive cells significantly increased in the surrounding muscle tissue, and were densely distributed in a large area at day 7 after particle injection. At day 14 of microparticle injection, the numbers of CD3 and CD68 positive cells in peripheral muscle tissue and tissue at the site of particle implantation were lower than those at day 7 (all P<0.01).@*CONCLUSIONS@#CPO/PCL particles have good oxygen release activity, low damage to tissue, and excellent biocompatibility.

Effect of penetrating resin on the surface structure, microhardness and color of enamel after bleaching / 中华口腔医学杂志

Objective: To investigate the effect of permeable resin on the surface structure, microhardness and color of tooth enamel after bleaching. Methods: Premolars extracted for orthodontic needs were selected (provided by the Department of Oral and Maxillofacial surgery of the first affiliated Hospital of Zhengzhou University) and randomly divided into A, B and C 3 groups. Each group was randomly divided into control subgroup, resin subgroup, bleaching subgroup and combined subgroup. Samples in the control subgroup did not receive any treatment. Those in the bleaching subgroup and combined subgroup were treated with cold light whitening. Those in the resin group and combined group were treated with permeable resin. Samples in the group A were observed by scanning electron microscope immediately after treatment and 2 weeks after treatment, and the microhardness of samples in the group B was measured before treatment, immediately after treatment and 2 weeks after treatment (the sample size of each time point was 8 in each subgroup). In group C, chromaticity was measured and chromatic aberration (ΔE value) was calculated before treatment, immediately after treatment and 1 and 2 weeks after treatment (10 samples in each subgroup). Results: Scanning electron microscope showed that the enamel surface of the resin subgroup and the combined group was smooth immediately after treatment, which was basically the same as that of the control subgroup, but covered with resin, and microporous defects and mineral deposits could be seen on the surface of the bleaching subgroup. Two weeks after treatment, the enamel surface of each subgroup was smooth, there was no obvious difference. Immediately after treatment, the microhardness of the control subgroup, resin subgroup, bleaching subgroup and combined subgroup were (354±33), (364±21), (411±30) and (350±17) HV, respectively (F=9.39,P<0.05). The microhardness of the bleaching subgroup was significantly higher than that of the other subgroups (P<0.05). There was no significant difference in microhardness among the four subgroups before treatment and 2 weeks after treatment (F=0.34, 2.75, P>0.05). Immediately after treatment, the ΔE values of the control subgroup, resin subgroup, bleaching subgroup and combined subgroup were 0.00±0.00, 2.29±1.86, 7.20±1.94 and 8.00±0.88, respectively (F=74.21,P<0.05); except that there was no significant difference between bleaching subgroup and combined subgroup (P>0.05), there were significant differences among the other subgroups (P<0.05). There was no significant difference in ΔE value among control subgroup, resin subgroup and bleaching subgroup at each time point (F=1.66, 0.30, 0.96, P>0.05). The difference in the combined subgroup immediately after treatment was significantly higher than that at 1 and 2 weeks after treatment (t=4.73, 4.23,P<0.05), but there was no significant difference between 1 and 2 weeks after treatment (t=0.75, P>0.05), and the color tended to be stable. Conclusions: When whitening healthy enamel, simple cold light whitening or cold light whitening combined with permeation resin can achieve whitening effect.

Effects and mechanism of hydrogen peroxide pretreatment with low molarity on oxidative stress induced apoptosis of mouse bone marrow mesenchymal stem cells / 中华烧伤杂志

Objective: To investigate the effects and mechanism of hydrogen peroxide (HP) pretreatment with low molarity on oxidative stress induced apoptosis of mouse bone marrow mesenchymal stem cells (BMSCs). Methods: The experimental research methods were used. BMSCs were isolated and cultured from two 2-week-old male BALB/c mice by the whole bone marrow culture method. The 3rd-7th passages of cells in logarithmic growth phase were used for the experiments after identification. According to the random number table (the same grouping method below), the cells were divided into 0 μmol/L HP group (without HP, the same below), 25 μmol/L HP group, 50 μmol/L HP group, 100 μmol/L HP group, 150 μmol/L HP group, 200 μmol/L HP group, 250 μmol/L HP group, and 300 μmol/L HP group in which cells were treated by the corresponding final molarity of HP, respectively. The apoptosis rate was detected by flow cytometry (n=4) after 24 hours of culture. The cells were divided into 0 μmol/L HP group, 25 μmol/L HP group, 50 μmol/L HP group, and 100 μmol/L HP group in which cells were treated by the corresponding final molarity of HP, respeclively. After 24 hours of culture, the protein expressions of B-lymphoma-2 (Bcl-2) and Bcl-2-related X protein (Bax) were detected by Western blotting, and the Bcl-2/Bax ratio was calculated (n=3). The cells were divided into 0 μmol/L HP group, 25 μmol/L HP group, 50 μmol/L HP group, 100 μmol/L HP group, 200 μmol/L HP group, and 300 μmol/L HP group in which cells were treated by the corresponding final molarity of HP, respectively. After 24 hours of culture, the protein expressions of glycogen synthase kinase-3β (GSK-3β) and phosphorylated GSK-3β (p-GSK-3β) were detected by Western blotting (n=3). The cells were divided into 0 μmol/L HP group, 50 μmol/L HP group, and 300 μmol/L HP group in which cells were treated by the corresponding final molarity of HP, respeclively, and HP pretreatment group with 50 μmol/L HP being added in advance for 12 h and then 300 μmol/L HP being added. After 24 hours of culture, the morphology and growth of cells were observed by inverted fluorescence microscopy (non-fluorescent condition) and immunofluorescence method, the apoptosis rate was detected by flow cytometry, the protein expressions of Bcl-2, Bax, cysteine aspartic acid specific protease-3 (caspase-3), caspase-9, cleavage caspase-3, cleavage caspase-9, GSK-3β, and p-GSK-3β were detected by Western blotting, and the Bcl-2/Bax ratio was calculated, with all the number of samples being 3. Data were statistically analyzed with one-way analysis of variance and Bonferroni test. Results: After 24 hours of culture, compared with that in 0 μmol/L HP group, the apoptosis rate of cells did not change significantly in 25 μmol/L HP group, 50 μmol/L HP group, or 100 μmol/L HP group (P>0.05) but increased significantly in 150 μmol/L HP group, 200 μmol/L HP group, 250 μmol/L HP group, and 300 μmol/L HP group (P<0.01). After 24 hours of culture, compared with that in 0 μmol/L HP group, the Bcl-2/Bax ratio of cells increased significantly in 25 μmol/L HP group and 50 μmol/L HP group (P<0.05 or P<0.01) but decreased significantly in 100 µmol/L HP group (P<0.05). After 24 hours of culture, compared with those in 0 μmol/L HP group, the protein expression of GSK-3β in cells showed no significant change in 25 μmol/L HP group and 50 μmol/L HP group (P>0.05), the protein expressions of p-GSK-3β in cells significantly increased in 25 μmol/L HP group and 50 μmol/L HP group (P<0.01), the protein expressions of GSK-3β and p-GSK-3β in cells in 100 μmol/L HP group showed no significant change (P>0.05), the protein expressions of GSK-3β in cells in 200 μmol/L HP group and 300 μmol/L HP group were significantly increased (P<0.05). but the protein expression of p-GSK-3β in cells in 200 μmol/L HP group and 300 μmol/L HP group was significantly decreased (P<0.05). After 24 hours of culture, the morphology and growth of cells in 0 μmol/L HP group and 50 μmol/L HP group were similar and normal; in contrast, the cells in 300 µmol/L HP group became smaller and round, with the cell protrusions being shorter or disappeared, the nucleus being cavitated, and the cell abscission being increased significantly; the morphology of most cells in HP pretreatment group was normal, with the shedding of cells being less than that in 300 µmol/L HP group, and the morphology of nucleus being normal. After 24 hours of culture, the protein expression of caspase-9 was similar among the four groups (P>0.05). Compared with that in 0 μmol/L HP group, the apoptosis rate and the protein expressions of cleavage caspase-9, caspase-3, and cleavage caspase-3 of cells in 50 μmol/L HP group showed no significant changes (P>0.05), the Bcl-2/Bax ratio of cells in 50 μmol/L HP group increased significantly (P<0.05), the apoptosis rate and the protein expressions of cleavage caspase-9, caspase-3, and cleavage caspase-3 of cells in 300 μmol/L HP group were significantly increased (P<0.01), while the Bcl-2/Bax ratio of cells in 300 μmol/L HP group was significantly decreased (P<0.05). Compared with those in 300 μmol/L HP group, the apoptosis rate and the protein expressions of cleavage caspase-9, caspase-3, and cleavage caspase-3 of cells were significantly decreased in HP pretreatment group (P<0.05 or P<0.01), while the Bcl-2/Bax ratio of cells was significantly increased in HP pretreatment group (P<0.01). After 24 hours of culture, the protein expressions of GSK-3β and p-GSK-3β of cells in 0 μmol/L HP group, 50 μmol/L HP group, 300 μmol/L HP group, and HP pretreatment group were 1.09±0.14, 0.62±0.17, 1.35±0.21, 0.74±0.34, 0.68±0.03, 0.85±0.08, 0.38±0.10, and 0.54±0.09, respectively. Compared with those in 0 μmol/L HP group, the protein expression of p-GSK-3β of cells was significantly increased in 50 μmol/L HP group (P<0.05) but significantly decreased in 300 μmol/L HP group (P<0.01), while the protein expression of GSK-3β of cells was significantly increased in 300 μmol/L HP group (P<0.05). Compared with those in 300 μmol/L HP group, the protein expression of GSK-3β of cells was significantly decreased in HP pretreatment group (P<0.01), while the protein expression of p-GSK-3β of cells was significantly increased in HP pretreatment group (P<0.01). Conclusions: The molarity of 50 μmol/L may be the optimal molarity of HP to pretreat mouse BMSCs, and 50 μmol/L HP pretreatment can antagonize mitochondrial pathway of oxidative stress induced apoptosis by inhibiting the activity of GSK-3β.

Hyperoside protects mouse spermatocytes GC-2 cells from oxidative damage by activating the Keap1/Nrf2/HO-1 pathway / 南方医科大学学报

OBJECTIVE@#To study the protective effect of hyperoside (Hyp) against ydrogen peroxide (H2O2)- induced oxidative damage in mouse spermatocytes GC-2 cells and explore the role of the Keap1/Nrf2/HO-1 pathway in this protective mechanism.@*METHODS@#GC-2 cells were treated with 2.5 mmol/L azaacetylcysteine (NAC), 50, 100, and 200 μmol/L hyperoside, or the culture medium for 48 h before exposure to H2O2 (150 μmol/L) for 2 h. CCK-8 assay was used to detect the changes in cell viability, and cell apoptosis was analyzed using flow cytometry. Enzyme-linked immunosorbent assay (ELISA) was used to detect the levels of superoxide dismutase (SOD), glutathione peroxidase (GSH-PX), catalase (CAT) activity and malondialdehyde (MDA) in the culture medium. Western blotting and RT-qPCR were used to detect the protein and mRNA expression levels of nuclear factor erythroid 2-related factor2 (Nrf2), Kelch-like ECH-associated protein 1 (Keap1), and heme oxygenase-1 (HO-1); the nuclear translocation of Nrf2 was detected using immunofluorescence assay.@*RESULTS@#Exposure to H2O2 significantly lowered the proliferation rate, reduced the activities of SOD, GSH and CAT, and obviously increased MDA content, cell apoptosis rate, and the expressions of Keap1 and Nrf2 mRNA and Keap1 protein in GC-2 cells (P < 0.05 or 0.01). Treatment of the cells prior to H2O2 exposure with either NAC or 200 μmol/L hyperoside significantly increased the cell proliferation rate, enhanced the activities of SOD, GSH-PX and CAT, and lowered MDA content and cell apoptosis rate (P < 0.05). Treatment with 200 μmol/L hyperoside significantly decreased the mRNA and protein expressions of Keap1 and increased the expressions of HO-1 mRNA and the protein expressions of Nrf2 and HO-1 (P < 0.05 or 0.01). Hyperoside also caused obvious nuclear translocation of Nrf2 in the cells (P < 0.05).@*CONCLUSION@#Hyperoside protects GC-2 cells against H2O2- induced oxidative damage possibly by activation of the Keap1/Nrf2/HO-1 signaling pathway.

Captopril related kidney damage: renal afferent arteriolar responses to angiotensin II and inflammatory signaling / 生理学报

Captopril can have nephrotoxic effects, which are largely attributed to accumulated renin and "escaped" angiotensin II (Ang II). Here we test whether angiotensin converting enzyme-1 (ACE1) inhibition damages kidneys via alteration of renal afferent arteriolar responses to Ang II and inflammatory signaling. C57Bl/6 mice were given vehicle or captopril (60 mg/kg per day) for four weeks. Hypertension was obtained by minipump supplying Ang II (400 ng/kg per min) during the second 2 weeks. We assessed kidney histology by periodic acid-Schiff (PAS) and Masson staining, glomerular filtration rate (GFR) by FITC-labeled inulin clearance, and responses to Ang II assessed in afferent arterioles in vitro. Moreover, arteriolar H2O2 and catalase, plasma renin were assayed by commercial kits, and mRNAs of renin receptor, transforming growth factor-β (TGF-β) and cyclooxygenase-2 (COX-2) in the renal cortex, mRNAs of angiotensin receptor-1 (AT1R) and AT2R in the preglomerular arterioles were detected by RT-qPCR. The results showed that, compared to vehicle, mice given captopril showed lowered blood pressure, reduced GFR, increased plasma renin, renal interstitial fibrosis and tubular epithelial vacuolar degeneration, increased expression of mRNAs of renal TGF-β and COX-2, decreased production of H2O2 and increased catalase activity in preglomerular arterioles and enhanced afferent arteriolar Ang II contractions. The latter were blunted by incubation with H2O2. The mRNAs of renal microvascular AT1R and AT2R remained unaffected by captopril. Ang II-infused mice showed increased blood pressure and reduced afferent arteriolar Ang II responses. Administration of captopril to the Ang II-infused mice normalized blood pressure, but not arteriolar Ang II responses. We conclude that inhibition of ACE1 enhances renal microvascular reactivity to Ang II and may enhance important inflammatory pathways.

A novel gene from the acidophilic bacterium Leptospirillum sp. CF-1 and its role in oxidative stress and chromate tolerance

BACKGROUND: Acidophilic microorganisms like Leptospirillum sp. CF 1 thrive in environments with extremely low pH and high concentrations of dissolved heavy metals that can induce the generation of reactive oxygen species (ROS). Several hypothetical genes and proteins from Leptospirillum sp. CF 1 are known to be up regulated under oxidative stress conditions. RESULTS: In the present work, the function of hypothetical gene ABH19_09590 from Leptospirillum sp. CF 1 was studied. Heterologous expression of this gene in Escherichia coli led to an increase in the ability to grow under oxidant conditions with 5 mM K2CrO4 or 5 mM H2O2. Similarly, a significant reduction in ROS production in E. coli transformed with a plasmid carrying ABH19_09590 was observed after exposure to these oxidative stress elicitors for 30 min, compared to a strain complemented with the empty vector. A co transcriptional study using RT PCR showed that ABH19_09590 is contained in an operon, here named the "och" operon, that also contains ABH19_09585, ABH19_09595 and ABH19_09600 genes. The expression of the och operon was significantly up regulated in Leptospirillum sp. CF 1 exposed to 5 mM K2CrO4 for 15 and 30 min. Genes of this operon potentially encode a NADH:ubiquinone oxidoreductase, a CXXC motif containing protein likely involved in thiol/disulfide exchange, a hypothetical protein, and a di hydroxy acid dehydratase. A comparative genomic analysis revealed that the och operon is a characteristic genetic determinant of the Leptospirillum genus that is not present in other acidophiles. CONCLUSIONS: Altogether, these results suggest that the och operon plays a protective role against chromate and hydrogen peroxide and is an important mechanism required to face polyextremophilic conditions in acid environments.

Genetic regulation of the ompX porin of Salmonella Typhimurium in response to hydrogen peroxide stress

BACKGROUND: Salmonella Typhimurium is a Gram negative pathogen that causes a systemic disease in mice resembling typhoid fever. During its infective cycle, S. Typhimurium is phagocytized by macrophages and proliferates inside a Salmonella containing vacuole where Salmonella is exposed and survives oxidative stress induced by H2O2 through modulation of gene expression. After exposure of Salmonella to H2O2, the expression of the porin encoding gene ompX increases, as previously shown by microarray analysis. Expression of ompX mRNA is regulated at a post transcriptional level by MicA and CyaR sRNAs in aerobiosis. In addition, sequence analysis predicts a site for OxyS sRNA in ompX mRNA. RESULTS: In this work we sought to evaluate the transcriptional and post transcriptional regulation of ompX under H2O2 stress. We demonstrate that ompX expression is induced at the transcriptional level in S . Typhimurium under such conditions. Unexpectedly, an increase in ompX gene transcript and promoter activity after challenges with H2O2 does not translate into increased protein levels in the wild type strain, suggesting that ompX mRNA is also regulated at a post transcriptional level, at least under oxidative stress. In silico gene sequence analysis predicted that sRNAs CyaR, MicA, and OxyS could regulate ompX mRNA levels. Using rifampicin to inhibit mRNA expression, we show that the sRNAs (MicA, CyaR and OxyS) and the sRNA:mRNA chaperone Hfq positively modulate ompX mRNA levels under H2O2 induced stress in Salmonella during the exponential growth phase in Lennox broth. CONCLUSIONS: Our results demonstrate that ompX mRNA is regulated in response to H2O2 by the sRNAs CyaR, MicA and OxyS is Salmonella Typhimurium.