A Research About The Affecting Of DEHP And DES On Rats Gene Expression Of Key Enzymes In The Process Synthesis Of Testosterone And The Mechanism Of Cryptorchidism

Objective SD rats,by exposing to phthalate di(2-ethylhexyl)phthalate(DEHP)and diethylstilbestrol(DES)during pregnancy(GND12-PND3),statisting male offspring cryptorchidism rate,measuring the amount of serum testosterone measured testosterone synthesis pathway key enzymes: cytochrome P450 cholesterol side-chain cleavage enzyme(P450scc)m RNA,acute regulatory protease(Star)m RNA and 3β steroid dehydrogenase(3β-HSD)relative expression of m RNA,preliminary inquiry environment mechanism of endocrine disruptors cryptorchidism rat offspring.Methods SPF rats were adaptive fed one week in shield animal laboratory environment,then male and female rats were caged in the the ratio of two to one.Taking vaginal smears test every 8 am to see if there is vaginal suppository under the microscope.Diary the day when sperm is find pregnancy zero days(GND0).48 pregnant SD rats were randomly divided into six groups:(1)control group(2)corn oil group(1ml / d)(3)DEHP low dose group(100mg/kd/d+1ml corn oil /d)(4)DEHP middle dose group(500mg/kg/d+1ml corn oil /d)(5)DEHP high doses group(750mg/kg/d+1ml corn oil /d)(6)DES(100mg/kg/d+1ml corn oil /d)。From GND12 day to PND3 the SD rat was administrated such treatment respectively.Thirty days after F1 pups were born,the incidence of cryptorchidism in male offspring rats in each group was calculated.The pathological section of testis were observated in each group.The amount of testosterone in rat offspring was measured in the chemiluminescence method.The relative expression of the cytochrome P450 cholesterol side-chain cleavage enzyme(P450scc)m RNA,acute regulatory protein(Star)m RNA enzymes and 3β steroid dehydrogenase(3β-HSD)was measured with real time PCR.Results 1.The exposure of a certain dose of DEHP and DES at embryonic period will cause prepubertal SD rat cryptorchidism.2.Leydig cells suffered varying degrees of clusing in middle,high-dose DEHP group and DES group.3.Compare with the normal group,the amount of testosterone(T)in high-dose DEHP group and DES group were significantly reduced(P < 0.05).4.DEHP and DES affect the gene expression process of key enzymes in the synthesis of testosterone formation.The expression levels of P450 SCC and 3β-HSD m RNA were reduced,the expression of star enzymes m RNA was increased in low,middle and high dose DEHP groups.The expression levels of P450 scc,3β-HSD,and star enzymes m RNA were reduced in DES group.Conclusions 1.Exposure to a dose of DEHP and DES in the critical period of embryonic development can lead to SD rat cryptorchidism.2.DEHP in the high dose group and DES group SD rat Leydig cells have different levels of aggregation.3.The amount of testosterone(T)in the high dose DEHP group and DES group were reduced and compare with the control group there was statistically significant.(P <0.05).4.DEHP and DES affect the gene expression of androgen formation pathway key enzyme P450 SCC,3β-HSD,Star.5.The mechanism of male offspring cryptorchidism causing by DEHP and SD may be reducing testosterone synthesis by affecting the key enzyme P450 scc,3β-HSD,Star gene expression.