Effects of lead exposure on development of heart and spine in zebrafish embryos / 环境与职业医学

Background Lead is widely distributed. Lead exposure interferes with early life development in zebrafish, but the mechanisms by which lead exposure affects skeletal development and cardiac development are not clear as yet. Objective To investigate the molecular mechanisms of bone development and cardiac development toxicity induced by lead acetate exposure. Methods Zebrafish embryos were exposed to different concentrations of lead acetate (0, 6, 12, 24, and 48 μmol·L−1) for 3 h post-fertilization (3 hpf) until 5 d post-fertilization (5 dpf). The malformation phenotypes of 5 dpf were counted, and the mRNA expressions of spinal development-related genes (bmp2b, bmp4, bmp9, runx2a, runx2b) and heart development-related genes (nkx2.5, myh6, myh7) were detected by quantitative PCR (qPCR). Expressions of genes of development-related regulatory pathways including Wnt/β-catenin pathway (wnt5a, wnt8a, wnt10a, β-catenin) and TGF-β pathway (tgf-β1, tgf-β2) as well as key molecule eph of Eph-Ephrin signaling were analyzed. Results At 5 dpf, the zebrafish in the lead acetate treated groups showed deformed phenotypes including spinal curvature and pericardial sac edema compared to the control group. In the lead acetate groups at 24 and 48 μmol·L−1, the spinal curvature deformity rates reached 26.47% and 71.52% (P<0.01) respectively. The qPCR results revealed that the expression levels of spinal development-related genes bmp2b, bmp4, bmp9, runx2a, and runx2b were downregulated in the 48 μmol·L−1 exposure group compared to the control group by 82.8%, 58.0%, 88.7%, 85.5%, and 69.2%, respectively (P<0.05 or P<0.01); the expression levels of heart development-related genes myh6, myh7, and nkx2.5 were down-regulated by 63.7%, 58.9%, and 55.2%, respectively (P<0.01); the expression levels of wnt8a and β-catenin in the Wnt/β-catenin pathway were down-regulated by 71.5% and 47.3% (P < 0.05 or P < 0.01), respectively; the expression level of tgf- β1 in the TGF-β pathway was down-regulated by 67.5% (P<0.01); the expression level of eph was down-regulated by 86.9% (P<0.01). Conclusion Lead acetate exerts developmental toxic effects on zebrafish heart and bone by down-regulating the expressions of genes related to spinal development and heart development, as well as inhibiting development-related Wnt/β-catenin and TGF-β pathways and Eph-Ephrin signaling, causing malformed phenotypes such as spinal curvature and pericardial sac edema.

Mechanism of paeoniflorin inhibiting apoptosis of hippocampal neurons of rats induced by lead acetate / 中华劳动卫生职业病杂志

Objective: To investigate the effect and underlying mechanism of paeoniflorin on hippocampal neuron apoptosis induced by lead acetate. Methods: In September 2020, primary hippocampal neuronal cells were isolated and cultured from fetal rats, and identified using cellular immunofluorescent. MTT assay was used to measure the cell viability to determine the concentration and time of lead acetate-induced hippocampal neuron apoptosis. MTT was also used to evaluate the effect of paeoniflorin concentration on the apoptosis of hippocampal neurons induced by lead acetate. According to the results, different concentrations of paeoniflorin were selected to intervene hippocampal neuron cells, after 24 h, lead acetate was added to the cells, meanwhile, blank and model groups were set up, the content of reactive oxygen species (ROS) , superoxide dismutase (SOD) , lactate dehydrogenase (LDH) , malondialdehyde (MDA) and Caspase-3 were measured. Extracellular signal regulated kinase (ERK) , phosphorylated ERK (p-ERK) , p38 mitogen -activated protein kinases (p38MAPK) , phosphorylated p38MAPK (p-p38MAPK) , c-Jun N-terminal kinase (JNK) and phosphorylated JNK (p-JNK) protein expression in hippocampal neuronal cells were determined by Western blotting. Results: The isolated and cultured hippocampal neurons were identified by immunofluorescence chemical staining and then treated with lead acetate, MTT results showed that lead acetate had the best toxicity effect when treated for 24 h at a concentration of 25 μmol/L. Paeoniflorin showed no cytotoxic effect on hippocampal neuronal cells when the concentrations below 80 μmol/L. Compared with the model group, the activity of hippocampal neuronal cells was significantly increased after treating with 20, 40 or 80 μmol/L paeoniflorin (P<0.05) . Compared with the blank group, the ROS activity, LDH release level, MDA content and caspase-3 content were significantly increased (P<0.01) , and the SOD activity was significantly decreased (P< 0.01) in the hippocampal neuronal cells of the model group. Compared with the model group, the ROS activity, LDH release level, MDA content and caspase-3 content were obviously decreased (P<0.05) , SOD activity was significantly increased (P <0.01) after hippocampal neuronal cells were treated with 40 or 80 μmol/L paeoniflorin. Relative to the model group, the ratio of p-ERK/ERK were significantly up-regulated (P<0.01) , while the ratios of p-p38MAPK/p38MAPK and p-JNK/JNK were significantly down-regulated after hippocampal neuronal cells were treated with 40 or 80 μmol/L paeoniflorin (P<0.05) . Conclusion: Paeoniflorin may down-regulate the expression of p-p38MAPK and p-JNK protein, up-regulate the expression of p-ERK protein, and inhibit the apoptosis of hippocampal neurons induced by lead acetate through the MAPK signaling pathway.

Protective effect of Rheum ribes extract against lead-induced hepatotoxicity in male rats

Abstract The effects of Rheum ribes on lead acetate levels and hepatic biochemical factors due to lead acetate toxicity were investigated. Forty male Wistar rats were designated into four groups: Control; lead acetate (receiving in drinking water at 0.6 g/L, daily); hydroalcoholic extract groups (200 and 400 mg/kg doses, gavage, once daily). Treatments were conducted for 10 days. On the 11th day, blood samples were collected to measure lead acetate levels and biochemical factors. Liver tissue samples were examined for histopathological changes. Lead serum levels were increased in lead acetate-treated rats (p<0.001). Lead acetate treatment was associated with a significant increase in liver tissue damage (p<0.001), while R. ribes extract prevented liver tissue damage (p<0.05). The levels of alanine aminotransferase and aspartate aminotransferase were significantly lower in the groups lead acetate + extract (two doses) than in the lead acetate group (p<0.001 and P<0.01, respectively), but alkaline phosphatase level, prothrombin time, partial thromboplastin time and international normalized ratio were not different between the lead acetate + extract groups and the lead acetate group. The results showed the inhibitory role of R. ribes on lead-induced hepato-toxicity. The results make Rhubarb a good candidate to protect against the deleterious effect of chronic lead intoxication after complementary studies

Neuromodulatory effects of ethyl acetate fraction of Zingiber officinale Roscoe extract in rats with lead-induced oxidative stress / 中西医结合学报

OBJECTIVE@#This study investigated the ameliorative potential of Zingiber officinale Roscoe extract against lead-induced brain damage in rats.@*METHODS@#Thirty male rats were divided into 5 groups of 6 rats each. Lead-acetate toxicity was induced by intraperitoneal injection (10 mg/kg body weight (b.w.)) in Groups B-E. Group A (control) and Group B (lead-acetate) were left untreated; vitamin C (200 mg/kg b.w.) was administered to Group C; ethyl acetate fraction from Z. officinale extract (200 and 100 mg/kg b.w.) was administered to Group D and E by oral gavage once daily for 7 days. Changes in the content of some key marker enzymes such as acetylcholinesterase (AChE), butyrylcholinesterase (BChE), monoamine oxidase (MAO), epinephrine, dopamine, Na/K-ATPase, catalase (CAT), superoxide dismutase (SOD) and glutathione peroxidase (GPx) as well as malonaldehyde (MDA) levels were determined in serum.@*RESULTS@#Exposure to lead acetate resulted in a significant decrease (P < 0.05) in the activities of BChE, AChE, Na/K-ATPase, SOD, CAT and GPx with a corresponding increase in the levels of MDA, xanthine oxidase, epinephrine, dopamine and MAO relative to the control group. Levels of all disrupted parameters were alleviated by co-administration of Z. officinale fraction and by the standard drug, vitamin C.@*CONCLUSION@#These results suggest that ethyl acetate fraction of Z. officinale extract attenuates lead-induced brain damage and might have therapeutic potential as a supplement that can be applied in lead poisoning.

The maturation state of the auditory nerve and brainstem in rats exposed to lead acetate and supplemented with ferrous sulfate / Estado de maturação do nervo auditivo e tronco encefálico em ratos expostos a acetato de chumbo e suplementados com sulfato ferroso

Abstract Introduction The literature has reported the association between lead and auditory effects, based on clinical and experimental studies. However, there is no consensus regarding the effects of lead in the auditory system, or its correlation with the concentration of the metal in the blood. Objective To investigate the maturation state of the auditory system, specifically the auditory nerve and brainstem, in rats exposed to lead acetate and supplemented with ferrous sulfate. Methods 30 weanling male rats (Rattus norvegicus, Wistar) were distributed into six groups of five animals each and exposed to one of two concentrations of lead acetate (100 or 400 mg/L) and supplemented with ferrous sulfate (20 mg/kg). The maturation state of the auditory nerve and brainstem was analyzed using Brainstem Auditory Evoked Potential before and after lead exposure. The concentration of lead in blood and brainstem was analyzed using Inductively Coupled Plasma-Mass Spectrometry. Results We verified that the concentration of Pb in blood and in brainstem presented a high correlation (r = 0.951; p < 0.0001). Both concentrations of lead acetate affected the maturation state of the auditory system, being the maturation slower in the regions corresponding to portion of the auditory nerve (wave I) and cochlear nuclei (wave II). The ferrous sulfate supplementation reduced significantly the concentration of lead in blood and brainstem for the group exposed to the lowest concentration of lead (100 mg/L), but not for the group exposed to the higher concentration (400 mg/L). Conclusion This study indicate that the lead acetate can have deleterious effects on the maturation of the auditory nerve and brainstem (cochlear nucleus region), as detected by the Brainstem Auditory Evoked Potentials, and the ferrous sulphate can partially amend this effect.

Resumo Introdução A literatura relatou a associação entre o chumbo e os efeitos auditivos, com base em estudos clínicos e experimentais. No entanto, não há consenso em relação aos efeitos do chumbo no sistema auditivo, ou sua correlação com a concentração do metal no sangue. Objetivo Investigar o estado de maturação do sistema auditivo, especificamente do nervo auditivo e do tronco encefálico, em ratos expostos ao acetato de chumbo e suplementados com sulfato ferroso. Método 30 ratos machos desmamados (Rattus norvegicus, Wistar) foram distribuídos em seis grupos de cinco animais e expostos a uma de duas concentrações de acetato de chumbo (100 ou 400 mg/L) e suplementados com sulfato ferroso (20 mg/kg). O estado de maturação do nervo auditivo e do tronco encefálico foi analisado pelo Potencial Evocado Auditivo do Tronco Encefálico antes e após a exposição ao chumbo. A concentração de chumbo no sangue e tronco encefálico foi analisada utilizando-se Espectrometria de Massa com Plasma Indutivamente Acoplado. Resultados Verificamos que as concentrações de Pb no sangue e no tronco encefálico apresentaram alta correlação (r = 0,951, p < 0,0001). Ambas as concentrações de acetato de chumbo afetaram o estado de maturação do sistema auditivo, a maturação foi mais lenta nas regiões correspondentes à porção do nervo auditivo (onda I) e dos núcleos cocleares (onda II). A suplementação com sulfato ferroso reduziu significativamente a concentração de chumbo no sangue e no tronco encefálico no grupo exposto à menor concentração de chumbo (100 mg/L), mas não para o grupo exposto à maior concentração (400 mg/L). Conclusão Esse estudo indica que o acetato de chumbo pode ter efeitos deletérios na maturação do nervo auditivo e do tronco encefálico (região do núcleo coclear), como detectado pelos potenciais evocados auditivos do tronco encefálico, e que o sulfato ferroso pode diminuir parcialmente esse efeito.

The establishment of the immortalized mouse brain microvascular pericytes model and its preliminary application in screening of cerebrovascular toxicants / 中华预防医学杂志

Objective@#To establish the immortalized mouse brain microvascular pericytes model and to apply to the cerebrovascular toxicants screening study.@*Methods@#Brain pericytes were isolated from 3 weeks of mice by tissue digestion. Immortalized pericyte cell line was constructed by infecting with LT retrovirus. Monoclone was selected to purify the immortalized pericyte cell line. The pericyte characteristics and purity were explored by immunocytochemistry. Cell proliferation was measured by using the Pomega MTS cell Proliferation Colorimetric Assay Kit. Pericytes were treated with 0, 160, 320, 640, 1 280, 2 560 μmol/L lead acetate, 0, 5, 10, 20, 40, 80 μmol/L cadmium chloride and 0, 5, 10, 20, 40, 80 μmol/L sodium arsenite in 24 hours. Cell toxicity of each group was determined by MTS assay, median lethal dose (LD50) was calculated in linear regression.@*Results@#Mouse brain pericytes were successfully isolated by tissue separation and enzyme digestion method. After immortalized by LT retroviruses, monoclone was selected and expanded to establish pericyte cell line. The brain pericytes exhibited typical long spindle morphology and positive staining for α-SMA and Vimentin. The proliferation of brain pericytes cell lines was very slowly, and the doubling time was about 48 hours. The proliferation of immortalized brain pericytes cell lines was very quickly, and the doubling time was about 24 hours. After lead acetate, cadmium chloride and sodium arsenite treatment for 24 hours respectively, gradual declines in cell viability were observed. The LD50 of lead acetate was 2 025.0 μmol/L, the LD50 of cadmium chloride was 36.6 μmol/L, and the LD50 of sodium arsenite was 33.2 μmol/L.@*Conclusion@#The immortalized mouse brain microvascular pericyte model is established successfully by infecting with LT retrovirus, and can be applied to screen cerebrovascular toxicants. The toxicity of these toxicants to immortalized mouse brain microvascular pericyte is in sequence: sodium arsenite,cadmium chloride, lead acetate.

Effect of Myricetin on the Spermatogenesis Obstruction Induced by Lead Acetate in Male Mice / 中国药学杂志

OBJECTIVE: To study the effect of myricetin and its mechanism for spermatogenesis obstruction caused by lead acetate in male mice. METHODS: The spermatogenesis obstruction of male mice model was built by intraperitoneal injection with lead acetate(20 mgkg-1) for 7 d. From the 2 d model made mice in low, medium and high doses myricetin were treated by myricetin, respectively(100, 200, 400 mgkg-1) by intraperitoneal injection for 42 d. The mice were sacrificed on day 43 for the measurement of the sperm density and sperm aberration rate. The levels of lactate dehydrogenase(LDH), nitric oxide(NO), tumor necrosis factor α(TNF-α) in testicular tissue homogenate, the content of malondialdehyde(MDA) in blood serum were assayed respectively. The pathological changes of testicular tissues were observed. RESULTS: Compared with the model group, sperm density was increased, the sperm aberration rate mice were decreased, the activities of LDH in testicular tissue homogenate were improved and the contents of NO in testicular tissue homogenate were decreased in different doses myricetin groups. The activities of TNF-α in testicular tissue homogenate and the content of MDA in blood serum were increased. Pathological change of testis showed there were decline of spermatogenic cells in levels and numbers and few spermiogenesis in most of seminiferous tubule in model group. Those change above could be reversed by myricetin. CONCLUSION: Myricetin has certain improvement on spermatogenesis obstruction of mice caused by lead acetateits, its mechanism may be related to decreasing NO, anti-oxidation and inhibiting inflammatory mediator.

Immunohistochemical and histopathological changes in the skin of rats after administration of lead acetate / Alteraciones inmunohistoquímicas e histopatológicas en la piel de ratas tras la administración de acetato de plomo

Lead acetate is a chemical compound. Sources of human exposure to this metal include many foods, drinking water and dust. The aim of this study was to determine the immunohistochemical and histopathological changes on the face skin after lead acetate application. Wistar Albino rats (180-200 g body weight) were divided into a controlled and lead acetate-exposed group. Rats received lead acetate at 500 ppm in their drinking water for 60 days. Both groups were fed with the same standard food, but lead acetate was added to the drinking water. During the experimental period, blood samples were drawn from the abdominal aorta of the anesthetised animals. At the end of exposure, body weight and blood lead levels were measured. Sections of rat facial skin were examined histopathological and immunohistochemical. In the group treated with lead acetate, minimal to slight multifocal hydropic degeneration of basal cell layer, depending on the thinning of the epidermis, the cellular degeneration in the dermis and a increase in the number of necrotic cells was observed in sebaceous glands of the hair follicle hemorrhage. The immunohistochemical results of the present work demonstrated an increase in Proliferating cell nuclear antigen (PCNA) immunoreactivity in skin specimens from lead acetate treated animals. Vimentin immunoreactivity was very dense in hair follicle of the subepidermal region. It was also strongly stained around the myoepithelial cells surrounding sebaceous and stromal cells.

El acetato de plomo es un compuesto químico. Las fuentes de exposición humana a este metal incluyen una gran variedad de alimentos, agua potable y el polvo. El objetivo fue determinar los cambios inmunohistoquímicos e histopatológicos en la piel de la cara después de la aplicación de acetato de plomo en ratas Wistar albinas (180 a 200 g de peso corporal) las que fueron divididas en un grupo control y otro expuesto al acetato de plomo. Las ratas expuestas recibieron acetato de plomo en dosis de 500 ppm en el agua que bebían durante 60 días. Ambos grupos fueron alimentados con el mismo pellet estándar. Durante el período experimental, se extrajeron muestras de sangre desde la parte abdominal de la aorta con los animales anestesiados. Al final de la exposición, se midió el peso corporal y los niveles de plomo en la sangre. Secciones de piel de la cara se examinaron y estudiaron con procediminetos histopatológicos e inmunohistoquímicos. En el grupo expuesto, se observó una degeneracion hidrópica multifocal desde mínima a ligera de la capa de células basales; dependiendo del adelgazamiento de la epidermis, se observó degeneración celular en la dermis y un aumento en el número de células necróticas en las glándulas sebáceas de folículos pilosos hemorrágicos. Los resultados inmunohistoquímicos demostraron un aumento de inmunoreactividad al antígeno nuclear de células en proliferación (PCNA) en las muestras de piel de los animales tratados con acetato de plomo. La inmunoreactividad a vimentina fue muy densa en los folículos pilosos de la región subepidermal. También se observó una fuerte tinción alrededor de las células mioepiteliales que rodean las células sebáceas y estromales.

Genotoxicity in lead treated human lymphocytes evaluated by micronucleus and comet assays.

Lead (Pb) which plays a significant role in modern industry is related to a broad range of physiological, biochemical, behavioural and genetical dysfunctions. Its exposure leads to an increased frequency of genetic aberrations in humans. Hence, this study was designed to assess the genotoxic effect of lead acetate at three dosage levels (10, 25 and 50 µg/mL) by employing: the Cytokinesis Block Micronucleus (CBMN) assay and the Comet assay in Peripheral Blood Lymphocyte Cultures. The results of this study revealed an increased level of DNA damage among treated groups. A significant increase in the tail length of comets and other indices was observed at 25 and 50 µg/mL concentrations comparatively. Thus, lead acetate induced single-strand breaks (SSB) and double strand breaks (DSB) in DNA, alkali-labile sites (ALS), oxidative DNA damage as well as DNA-DNA/DNA-protein/DNA-metal cross linking as evidenced by the Comet assay. The chromosome breakage, DNA misrepair, chromosome loss and telomere end fusion were determined by the Micronucleus assay. Micronucleus frequency in treated lymphocytes was significantly higher as compared to controls. Nucleoplasmic bridges increased significantly and Nuclear buds increased at higher two doses only in exposed cultures. Thus, these assays are better indices for lead induced genotoxicity and metal-nucleus interactions.

Role of copper transporter protein in copper accumulation in C6 cells induced by lead exposure / 中国职业医学

OBJECTIVE: To investigate the role of copper transporter protein and copper chaperones in copper accumulation in glioma cell line C6 cells induced by lead acetate exposure. METHODS: i) CCK-8 assay was used to determine the proper lead acetate dose by treating the cells with lead acetate at the final concentration of 0-50 μmol / L for 24. 0 hours. ii) C6 cells were divided into control group and lead-exposure group,treated with 0 and 10 μmol / L lead acetate respectively for24. 0 hours,and then cultured in 2 μmol / L copper chloride for 0. 0,0. 5,1. 0,2. 0,4. 0 and 8. 0 hours; inductively coupled plasma mass spectrometry was used to detect the levels of copper and lead in the cells. Real-time polymerase chain reaction was used to detect the mRNA expression of copper transporter 1( CTR1),divalent metal transporter 1( DMT1),copper-transporting ATPase α polypeptide / β polypeptide( ATP7 A and ATP7B), antioxidant 1 copper chaperone( ATOX1),cytochrome c oxidase copper chaperone( COX17),and copper-chaperone-for-superoxide dismutase( CCS).Laser con-focal microscopy was applied to detect the protein expression of CTR1 and ATP7 A in cells. RESULTS: i) CCK-8assay proved that the 10 μmol / L lead acetate treatment did not affect C6 cells proliferation( P > 0. 05). Thus the final concentration of 10 μmol / L lead acetate was chosen as the treatment dose in later experiments. ii) After 10 μmol / L lead acetate exposure for 24. 0 hours,the lead and copper levels of C6 cells in lead-exposure group were higher than those in the control group( P < 0. 01),but there was no statistical significant difference in the C6 cell survival rate between these two groups( P > 0. 05). After cells were treated with copper,the C6 cell survival rate of lead-exposure group was lower than that in the control group( P < 0. 01). The interactive effect of copper level showed statistical significance between lead exposure and cooper treatment time( P < 0. 01). At the 5 time points from 0. 5-8. 0 hours after exposure to copper,the copper levels in lead-exposure group were higher than those of control group( P < 0. 05). The copper levels in the control group reached a peak after exposure to copper for 2. 0 hours,and maintained at a stable level till the time point of 8. 0hours. The copper levels of lead-exposed groups increased with the increasing time of copper exposure and there was a time-effect relationship,and they reached to the peak at the time point of 8. 0 hours. After 10 μmol / L lead acetate exposure for 24. 0 hours,compared with control group,the CTR1 and DMT1 mRNA relative expression levels in leadexposed group increased by 113. 00% and 36. 00% respectively( P < 0. 01),and the ATP7 A mRNA relative expression level decreased by 25. 00%( P < 0. 01). The protein expression of CTR1 increased by 76. 04%( P < 0. 01),and the protein expression of ATP7 A decreased by 16. 0%( P < 0. 01). There was no significant difference in the mRNA relative expression levels of ATP7 B,ATOX1,COX17 and CCS between the two groups( P > 0. 05). CONCLUSION: Lead acetate exposure can lead to increase accumulation of copper in C6 cells with increasing exposure time showing a time-effect relationship. The increased protein expression of CTR1 and decreased protein expression of ATP7 A might be one of the mechanisms of inducing copper accumulation in cells after the lead acetate exposure.

Inhibitory effect of lead acetate on TRPA1 channel in mice and humans / 中国药理学与毒理学杂志

OBJECTIVE To investigate the inhibitory effect of lead acetate on transient receptor potential A1(TRPA1)channel. METHODS TRPA1-mediated calcium influx in mice dorsal root ganglion(DRG) neurons and HEK293 cells expressing nouse TRP1 (mTRPA1) and human TRPA1 (hTRPA1) was recorded by intracellular calcium imaging. TRPA1-mediated currents were detected by two-electrode voltage clamp. RESULTS Lead acetate 3.0 and 10.0μmol·L-1 inhibited external calcium influx in DRG neurons by(36.7 ± 4.1)% and(79.4 ± 3.1)%(n=5),respectively. The inhibitory effect of lead acetate on hTRPA1-mediated current was concentration-dependent. Lead acetate 0.3, 1.0, 3.0, 10.0 and 30.0μmol · L-1 inhibited the amplitudes of currents by(1.0 ± 0.7)%,(11.6 ± 0.8)%,(57.7 ± 3.2)%,(93.6 ± 2.6)%and(91.2±2.0)%(n≥4),respectively,with the IC50 2.4μmol·L-1. CONCLUSION TRPA1 channel may be an endogenous target of lead. Lead acetate inhibits TRPA1 channel at a very low concentration.

Effects of Regular Treadmill Exercise on a DNA Oxidative-Damage Marker and Total Antioxidant Capacity in Rat Hippocampal Tissue

BACKGROUND AND PURPOSE: Regular exercise can result in changes in the levels of oxidative stress in the hippocampus; however, little attention has been paid to physical-activity-induced neuronal protection to exposure to lead compounds. This study investigated the effects of regular treadmill exercise on a DNA oxidative-damage marker [8-hydroxy-2'-deoxyguanosine (8-OHdG)] and the total antioxidant capacity (TAC) of hippocampal tissue in lead-acetate exposed rats. METHODS: This study investigated the effects of 8 weeks of regular treadmill exercise on 8-OHdG and the TAC of hippocampal tissue in lead-acetate-exposed rats. Wistar rats were randomly divided into four groups: baseline, sham (control), lead, and exercise+lead. The exercise program involved running on a treadmill with increasing intensity five times a week for 8 weeks. Animals in the lead and exercise+lead groups received lead acetate at 20 mg/kg body weight intraperitoneally three times weekly for 8 weeks. Animals in the sham group received solvent (ethyl oleate) at 30 mg/kg body weight three times weekly for 8 weeks. TAC and 8-OHdG were measured by spectrophotometric and ELISA techniques, respectively. Data were analyzed by ANOVA and Tukey's post-hoc test with a significance cutoff of p≤0.05. RESULTS: The level of 8-OHdG and the TAC were significantly higher and lower, respectively, in the lead group than in the baseline and sham groups (p<0.01). However, the 8-OHdG level and TAC value in hippocampal tissue were significantly decreased and increased, respectively, in the exercise+lead group relative to the lead group (p<0.05). CONCLUSIONS: The TAC of hippocampal tissue may be directly associated with neural protection mechanisms of exercise following lead acetate injection, and the beneficial effects of regular exercise in preventing hippocampal neuronal damage could be due to decreased hippocampal oxidative stress such as reflected by a lower 8-OHdG level and increased TAC.

A Comparative Study of the Histological Changes in Cerebral Cortex, Hippocampus, Cerebellum, Pons & Medulla of the Albino Rat Due to Lead Toxicity.

Introduction: Lead, a heavy metal is well known for its toxic effects on the central nervous system. Clinically, overall effects of lead on different organ system are called plumbism. Diverse writing can be seen on the subject, but rarely there has been a comparison in any of these writings on different parts within the brain of the changes happening as the result of lead exposure. This study was taken up to draw a comparison and correlation of damaging effects on different parts of brain at microscopic level as a result of lead toxicity so that the affected elements in the tissue can be further connected to the histopathological and clinical outcomes of the lead toxicity. Materials and Methods: To conduct the study albino rats of Charles Foster strain were administered orally with 4% lead acetate in drinking water. The behavioral and clinical changes during the period of lead administration were closely observed that extended from irritability, agitation and aggressive behavior in the beginning to drastic fall in activity, indifference towards varieties of stimulus and severe motor deficit. At the end of an average of 17 days the rats were sacrificed for both gross and microscopic examination of brain for changes in the cerebral cortex, hippocampus, cerebellum, pons & medulla. The elements of the tissue observable as per the selected staining were the neurons, fibers, glia & the vessels. Results: The changes showed up with similarities between different parts as the shrinkage of neurons, damaged fibers, stunting of cell processes and increased glial cell population, whereas there were dissimilarities with regards to the extent of shrinkage of neuron and distribution of perineuronal spaces, vacuoles & the glial cells. Discussion and Conclusion: The comparative picture of the changes as a result of lead exposure showed widespread damage to nearly all the elements of the nervous tissue with reactive changes e.g. gliosis, and variations in the extend of changes in the selected brain parts. As a result these changes observed can be of used to correlate in the overall outcome of plumbism in relation to the functions of different parts of the brain.

Expression changes of HIF-1α, ROCK-2, FoxM1 in the lead acetate-induced injury in PC12 cells / 中国药理学通报

Aim To investigate the expression and im-plication of HIF-1α, ROCK-2 , FoxM1 in PC12 cell in-jury induced by lead acetate. Methods PC12 cells were treated with lead acetate at the doses of 100 , 200 and 400 μmol·L-1 . The cell viability was determined by MTT reduction assay and LDH assay, the intracellu-lar production of oxygen species was measured by as-sessing SOD and MDA levels, cell apoptosis was deter-mined by Hoechst 33342 staining, the expressions of HIF-1α, ROCK-2 , FoxM1 , Bcl-2 and Bax were deter-mined by immunoblotting analysis. Results Lead ac-etate induced cell injury in PC12 cells in a dose-de-pendent manner, and it potentiated oxygen radical pro-duction and cell apoptosis. In addition, lead acetate enhanced HIF-1α and ROCK-2 expressions, increased Bax/Bcl-2 ratio and decreased FoxM1 expression. Conclusion Lead acetate can induce PC12 cell apop-tosis, which may be related with the expressions of HIF-1α, ROCK-2 and FoxM1 . Cellular oxidative stress may contribute to the injury as well.

Antienzymetic Action of Lead Acetate and its Possible Reversal by Antioxidant in Testicular Tissue of Swiss Albino Mice During Pubertal Phase of Life.

Lead intoxication has been associated with male reproductive toxicity in experimental animals and lead may have the potential to produce adverse effects on enzymatic activity in testicular tissue of Swiss albino mice. The present study was undertaken to investigate the ability of antioxidant (Vitamin E) to protect against lead acetated (LA) induced testicular enzymatic toxicity in male albino mice during pubertal phase of life. The weight of testis, caput epididymidis, cauda epididymidis, vas deferens and testicular enzymatic activity (Glutathione peroxidase (GSH-Px), Succenate dehydrogenase (SDH), 65–3β hydroxysteroid dehydrogenase (65–3β–HSD) and 17β–hydroxysteroid dehydrogenase (17β–HSD) were studied. Administration of LA at a dose of 1.25mg/kg body weight for 45 days lowered the weights of testes, caput epididymidis, cauda epididymidis, vas deferens and decreased the activities GSHPx, SDH, 65–3β–HSD and 17β–HSD. Coadministration of vitamin E (2 mg/kg BW) to the LA group restored all the parameters cited above to near the control values. Therefore, this study revealed that vitamin E has beneficial effects against LA induced enzymatic toxicity in testicular tissue of mice.

Lead Acetate Induced Histopathological Alterations in Renal Tissue of Balb-C Mice (Mus Musculus).

The aim of the study was to evaluate the histological alterations induced by lead intoxication in the mice kidney. Eighteen mice (20-24g body weight) were divided into 3 groups of 6 animals each. First group served as control and was given normal saline solution as vehicle. The second and third groups were orally administered (10 and 150 mg/kg body weight) lead acetate respectively for 40 days. After 40 days of lead acetate treatment, 3 mice from each group were sacrificed and the rest were left for 80 days without any supplement. Kidneys were excised for histological studies. The findings indicated that chronic exposure to subtoxic concentrations of lead acetate produced progressive tubular, glomerular and interstitial damage that include tubular dilation, vacuolar degeneration, atrophy of glomerular tuft, interstitial edema and congestion of blood capillaries. Lesions were more pronounced in animals exposed to high dose. However mice at 80 days showed improvements in lead induced histopathological alterations. The severity of lesions of lead toxicity depends on the dose of lead and period of exposure.

Pyramidal Layer thinning, Shrunken Neurons and Deep Vacuolation In Hippocampus due to the Organic Lead Induced Toxicity.

Lead, a known heavy metal exerts its toxicity on different organ systems of which the neurotoxicity is a considered to a significant consequence. The organic lead exposure on the hippocampus, that plays a significant role in the formation of short and long term memory, navigation and also participates in the limbic system in the brain, was studied. The resulting effects were the thinning of neuron layers, vacuolation and reduction in overall cell population of neurons, thereby showing the primary effect on the pyramidal layers of the hippocampus.

Effects of sub-lethal exposure of lead acetate on histopathology of gills, liver, kidney and muscle and its accumulation in these organs of Clarias gariepinus

The aim of this work was to study the effects of sub-lethal exposure of lead acetate on the histopathology of the gills, liver, kidney and muscle and its accumulation in these organs of Clarias gariepinus. Results showed that lead accumulation in the tissues of C. gariepinus was dependent on the exposure period and lead concentration. Gills and liver were the predominant storage tissue and the order of accumulation in tissues was gill > liver > kidney > muscle. Some structural changes were observed in different organs, especially in the gills of the fishes exposed to lead acetate. Epithelial hypertrophy and epithelial lifting were apparent in the gills of exposed fishes. The degeneration of cytoplasm and secondary lamellae was also observed. Necrosis of hepatocytes was apparent. Glomerular expansion and gaps between the muscular bundles were found in the fishes exposed to lead acetate.

Absorption levels and morphological features of fetal organs in wistar rats treated with lead acetate / Niveles de absorción y características morfológicas de los órganos fetales en ratas wistar tratadas con acetato de plomo

Lead is one of the heavy metals most used in industry. Poisoning due to long-term lead exposure is known as saturnism, and is an occupational illness that has been known for many years. Lead is highly toxic and can compromise the structural and functional patterns of organs and systems. The aim of this study was to examine the lungs and kidneys of fetuses from female Wistar rats exposed to lead acetate. In this study, the lungs and kidneys of 20 fetuses from female rats that had previously been treated with lead acetate were dissected, fixed, embedded in paraffin and stained with hematoxylin and eosin. Macroscopic changes to the shape, color and consistency of organs from fetuses treated with this heavy metal were observed, in comparison with organs from control fetuses. Microscopic lesions characterized by vascular sclerosis, cell atrophy or hyperplasia, progressive interstitial fibrosis, inclusion bodies containing lead acetate and glomerular sclerosis were found in the kidneys. The lesions found in the lungs consisted of destructuring of the parenchyma, impregnation with lead acetate, formation of fibrosis, extravasation of vascular fluids, reduction of the alveolar spaces and formation of alveolar edema. These changes were correlated with the level of lead acetate absorption, as determined using atomic spectrophotometry.

El plomo es un metal pesado utilizado en la industria. El envenenamiento debido a la exposición prolongada por plomo es una enfermedad profesional conocida por muchos años. La toxicidad del plomo es muy expresiva y puede poner en peligro el modelo estructural y funcional de los órganos y sistemas. El objetivo de este estudio fue examinar los pulmones y riñones de fetos de ratas Wistar expuestos al acetato de plomo. En este estudio, 20 fetos de ratas Wistar previamente tratados con acetato de plomo durante la gestación, tuvieron sus órganos disecados, fijados, incluidos en parafina y teñidos con hematoxilina y eosina. Macroscópicamente, los órganos fetales tratados por este metal fueron comparados con los órganos de fetos controles en relación a forma, color y consistencia. Microscópicamente, se encontraron lesiones en el riñón que se caracterizaron por esclerosis vascular, atrofia o hiperplasia de células, fibrosis intersticial progresiva, presencia de cuerpos de inclusión que contenían acetato de plomo y esclerosis glomerular. En el pulmón se observó desorganización del parénquima impregnado con acetato de plomo, formación de fibrosis, líquido intersticial, reducción de los espacios alveolares y edema alveolar. Estos cambios se correlacionaron con el nivel de absorción de acetato de plomo, determinado por espectrometría atómica.

The discrimination of d-tartrate positive and d-tartrate negative S. enterica subsp. enterica serovar Paratyphi B isolated in Malaysia by phenotypic and genotypic methods

Serotyping is not suffi cient to differentiate between Salmonella species that cause paratyphoid fever from the strains that cause milder gastroenteritis as these organisms share the same serotype Salmonella Paratyphi B (S. Paratyphi B). Strains causing paratyphoid fever do not ferment d-tartrate and this key feature was used in this study to determine the prevalence of these strains among the collection of S. Paratyphi B strains isolated from patients in Malaysia. A total of 105 isolates of S. Paratyphi B were discriminated into d-tartrate positive (dT+) and d-tartrate negative (dT-) variants by two lead acetate test protocols and multiplex PCR. The lead acetate test protocol 1 differed from protocol 2 by a lower inoculum size and different incubation conditions while the multiplex PCR utilized 2 sets of primers targeting the ATG start codon of the gene STM3356. Lead acetate protocol 1 discriminated 97.1% of the isolates as S. Paratyphi B dT+ and 2.9% as dT- while test protocol 2 discriminated all the isolates as S. Paratyphi B dT+. The multiplex PCR test identifi ed all 105 isolates as S. Paratyphi B dT+ strains. The concordance of the lead acetate test relative to that of multiplex PCR was 97.7% and 100% for protocol 1 and 2 respectively. This study showed that S. Paratyphi B dT+ is a common causative agent of gastroenteritis in Malaysia while paratyphoid fever appears to be relatively uncommon. Multiplex PCR was shown to be a simpler, more rapid and reliable method to discriminate S. Paratyphi B than the phenotypic lead acetate test.