The aim of this study was to investigate the effect of manganese on the hepatic cytochrome P450 enzyme system in cocks.400 fifty-day old Hy-line brown cocks were randomly divided into four groups.The cocks in four groups were respectively fed with the basal diet containing 0,600,900 and 1 800 mg·kg-1 MnCl2 to establish the sub-chronic manganism model.After 30,60 and 90-day treatment,the livers in every group were collected to detect the activity of microsomal cytochrome P450 enzyme system and the transcription level of CYP2H1 gene.The contents of cytochrome P450 and b5,the activities of aminopyrin-N-demethylase(AND) and aniline-4-hydroxylase(AH) were gradually declined with the increase of manganese in diet.The high dose group was significantly lower than the control group while there were no difference between the low and middle dose group and the control group.There were no markedly changes in the activities of NADPH-cytochrome C reductase(CR) and erythromycin-N-demethylase(ERND).The activity of CR declined at 30 and 60 d,but increased at 90 d.Besides,the CR activity of the high dose group was significantly higher than that in the control group(P0.01).The activity of ERND increased at 30 d but no markedly tendency appeared at 60 and 90 d.The ERND activity in the high dose group was significantly higher than that in the low dose group(P0.01).The transcription level of CYP2H1 mRNA in the low dose and high dose group at 30 d,the middle dose group at 60 d,and the low dose group at 90 d were higher than that in the control group.The transcription level of CYP2H1 mRNA in other treatment groups were lower than that in the control group.These results indicated that manganism could significantly changes the activities of microsomal-cytochrome P450s and the transcription level of CYP2H1 mRNA.

To study the effect of the disequilibrium of calcium homeostasis on the apoptosis of the neurons in the chicken brain induced by manganese in vitro,neurons cultured in vitro were chosen as the research object.Neurons were cultured in the DMEM for 24 h with the final concentration of 0,1.5,2 and 2.5 mmol·L-1 MnCl2.The mitochondrial membrane potential(ΔΨm) and phosphatidylserine(PS) were assessed by flow cytometry.DNA fragmentations were detected by DNA Ladder.The calcium ion concentration within neurons(i) was detected using the Fura3/AM as the probe and expression level of intracellular CaM mRNA was detected by FQ-PCR.The results showed that ΔΨm tended to decline the expansion of the pore,DNA fragmentations and i were increased.Moreover,the expression of CaM mRNA was decreased.This study indicated that MnCl2 could decrease the activity of CaM,ΔΨm and increase result in apoptosis of the chicken neurons.

To determine the effect of MnCl2 exposure on apoptosis of cock sertoli-germ cell and on expression of Bak and Bcl-x mRNAs,cock sertoli-germ cells were cultivated in DMEM with the final concentrations of 0,2,3 and 4mmol/L MnCl2 respectively for 24h.The apoptosis was determined by TUNEL assay,and the expression amounts of Bak and Bcl-x mRNAs were examined by real-time fluorescence quantitative PCR.In result,compared with control group,the apoptosis index(AI) of cock sertoli-germ cell significantly increased(P0.01),the expression of Bak mRNA increased(P0.01) while the expression of Bcl-x mRNA decreased(P0.01) in 2,3 and 4mmol/L MnCl2 treatment groups.The result indicated that MnCl2 was able to induce apoptosis of cock sertoli-germ cell by up-regulating the expression of Bak mRNA and down-regulating the expression of Bcl-x mRNA.

The aim of this study was to discuss the role of mitochondria mediated apoptosis pathway in Sertoli-germ cell apoptosis induced by manganese in cocks.Cock Sertoli-germ cells were cultivated in the DMEM for 24 h added with MnCl2,whose final concentrations were 0,2,3,and 4 mmol·L-1 respectively.The apoptosis was detected by AO/EB double staining.Mitochondrial transmembrane potential was detected by flow cytometer.Expression of Cytochrome c(Cytc)in cytolymph was detected by western blotting.The activities of Caspase-9,3 were examined by spectrophotography.Compared with control group,the apoptosis index(AI)of cock Sertoli-germ cells was significantly increased(P0.01),mitochondrial transmembrane potential was significantly decreased(P0.01),expression of Cytc in cytolymph was increased,and the activity of Caspase-9,3 were increased(P0.01)in 2,3,and 4 mmol·L-1 MnCl2 group.The apoptosis mediated by mitochondria pathway was one of the reproductive toxic mechanisms caused by manganese.

To explore the roles of mitochondria complex and oxidative stress in the apoptosis of chicken embryonic neurons exposed to MnCl2,the content of ROS and GSH,the activity of mitochondria respiratory chain complex and apoptosis index in neurons cultivated in DMEM with the final concentration of MnCl2 (0,1.5,2.0,2.5mmol/L) for 24h were detected by using the kits.In result,with the increase of the concentration of MnCl2,the activities of mitochondria respiratory chain complexes Ⅰ,Ⅱ,Ⅲ and Ⅳ and the content of GSH decreased.But in 1.5mmol/L MnCl2 environment,the activity of mitochondria respiratory chain complexⅤ decreased,the content of ROS and the apoptosis index increased,and morphological changes of apoptosis were observed in the neurons.These results indicated that MnCl2 could induce the apoptosis of the chicken embryonic neurons which was performed through oxidative stress caused by decreasing the activities of mitochondria respiratory chain complexes.