| Objective: In recent years, along with the economic development andsocial progress, human survival environment pollution is more and moreserious, and the destruction of the environment also lead to the gradualdecrease in male reproductive ability directly or indirectly, but the mainperformance of the decrease in male reproductive ability is the influence of theinternal or external factors on the testis and sperm.The decreased fertility ofmale has direct influences on the development of the future,the factor thatleads to the result is many and varied,and the harm of environmental hormoneto reproduction is being paid more and more attention by the academic circles.Bisphenol A (BPA) belongs to alkyl phenolic environmental hormone, and itschemical structure and estrogen similar, with like estrogen function,is a kindof hormone active material which has been proved by animal experiment.BPA is widely used in the industrial products, such as plastic products, thepolystyrene polyester production, carbonic acid and so on,BPA can dips intothe beverage and food through the container made from these materials,thusenters into human body and causes some damage.At present,the estrogen-likeactivity of BPA is also the research focus both at home and abroad, butdomestic and foreign scholas have less study of its reproductivetoxicity.Currently the researches of reproductive toxicity of BPA are mainlyfocused on morphologic changes of testicular reproductive cells,and manyscholars observe the changes of forms of reproductive cells and sperms withintheir testises by studying pregnant rats or pups both infected by BPA, there aresome studies show that environmental hormone can lead to the unusual growthof male reproductive system,at the meantime still have some researches showthat male sterility directly connects to the apoptosis of reproductive cell. There are relations between the apoptosis of reproductive cell within the testis andincreased NOS expression leading to increased No of its orannization,and theapoptosis of reproductive cell is also influenced by other factors, among them,the telomeres and cell apoptosis also has a close connection. This experimentthrough the different doses of bisphenol A (BPA) infecting rats to study theeffects of endogenous injuries that BPA on male testicular sperm cells and theexpression of telomerase, telomerase reverse transcriptase (TERT), nitricoxide (NO) and nitric oxide synthase (NOS), is to explore the effects of theenvironmental hormone (EDs) on human reproductive capacity, and then toillustrate the possible mechanism of reproductive toxicity of BPA.Methods:Choose48health male SD rats which are standard in theexperiment,divide them into four groups: the control group, low dose group,medium dose group and high dose group. Infected methods:Dissolve BPA ineating corn oil,configurate into2,20, and200mg/(kg*d) three kinds ofconcentration,and the volume of filling stomach is1ml/d,filling stomach timeis8:00a.m. everyday; feed the control group same volume eating corn oil,fillthe stomach for eight weeks continuously,calculate testicular visceracoefficient,take epididymis to measure sperm density, activity rate anddeformity rate, use immunohistochemical method to detect the germ cellactivity, nitrate reductase method to detect testicular tissue NO content andchemical colorimetric method to detect testicular tissue NOS activity.ApplySPSS13.1statistical software,use single factor variance analysismethod,choose LSD method between groups,and employ linear correlationanalysis to describe the relationship between two variables count. Inspectionstandards: there was statistical difference, alpha=0.05, P <0.05.Result: Rats testicular tissue pathology observation:there was littlechange between the low dose group injected with BPA and the control group,the seminiferous tubules of medium and high dose group arranged loosely, thegerm cells in the lumen were disarranged and loose, Leydig showed differentdegree edema,and mesenchymal cells distributed loosely. the bodyweights,testes,epididymis and the coefficient of testicular viscera: with the increase of the dosage of BPA,the weight of rats,right testis and epididymisdecrease gradually, compared with the control group,the body weights,righttestes,right epididymis and viscera coefficient of the infected medium andhigh dose group were statistically significant(p<0.05),and the wight of rats,right testis and epididymis had negative correlation with the dosage infectedby BPA(r=-0.844，p＜0.001; r=-0.903，p＜0.001; r=-0.605,p＜0.001);Sperm quality analysis:the density and survival rate decreased with theincrease of individual dosage.Compared with the control group,the mediumand high dose group reduced significantly,there was significantly statisticaldifference (P <0.05).The total deformity rate of rat sperm was muchhigher,compared with the control group,the medium and high dose group wasstatistically significant (P <0.05). Spermatogenic cell express detection:TERTpositive products were expressed in the spermatogenic cell of each dosegroup,compared with control group, both groups had different degreedecrease,the low dose group had no statistical signification (P>0.05),,therewas statistical signification between the medium and high dose group and thecontrol group (P <0.05). NO and NOS expression detection:the content ofNO and the NOS activity in the testicular tissue had increased in each dosegroup,compared with the control group,the low dose group which was infectedby BPA had no particular rise,there was no statistical signification(P>0.05),whereas the medium and high dose group which was infected byBPA had a particular rise,and had a statistical differrence (P <0.05).Conclusion: Certain dosage BPA can reduce telomerase activity byinhibiting the TERT expression of spermatogenic cel,and then less thegeneration of sperm, reduce the quality and increase the abnormal rate. BPAof different dosages can enhance NOS activity in the rat testicular tissue,thusgenerating excessive NO which is a important reason of leading to the lowerreproductive performance.. |
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