Effects Of DEHP On Sex Hormones And Their Related Enzymes Of Hippocampus In Infant Rats

PartⅠ The General Toxic Effect of DEHP Exposure in Infant RatsObjective: To study the general toxic effect of DEHP exposure on infant rats.Method: Forty female SD rats, 4-week-old, were randomly divided into 5 groups:control group, 0.5、 5 、 50 and 500 mg/kg/d DEHP group. And 40 male SD rats,4-week-old, processing as the female. The rats were given 0.2 ml/100 g liquid by gavage for 4 week. All rats were decapitated after the last gavage. The heart, liver,kidney, spleen, lung, kidney, brain and ovary or testicles were weighted and organ coefficients were calculated.Result: In female rats, no significantly differences of weight gains in four DEHP groups were found in all the four time points(P>0.05); no obvious pathological changes were found in the ovarian; the liver and kidney coefficients of 50mg/kg/d DEHP group increased significantly(P<0.05,P<0.01).In male rats, compared with the control group, weigh gains of 0.5 mg/kg/d DEHP group and 500 mg/kg/d DEHP group increased significantly(P<0.05). During this period, the intercellular space of 500mg/kg/d DEHP group significantly increased together with a significantly increase in the lumen of seminiferous wre stenosis.The testicle coefficient of 500mg/kg/d DEHP group decreased significantly(P<0.05)while the liver coefficient of 500mg/kg/d DEHP group increased significantly(P<0.01).Conclusion: The liver, kidney and testicles may be affected by DEHP exposure.What’s more, those effects showed gender difference.Part Ⅱ The Effect of DEHP Exposure on the Oxidative Stress of Serum and Ovaries or Testicle in Infant RatsObjective: To investigate the effect of DEHP exposure on the oxidative stress of serum and ovaries or testicles in infant rats.Method: SOD、MDA、GSH and ACP kits were used to evaluated the oxidative stress.Result: In female rats Compared with the control group, the levels of MDA and ACP of ovaries increased significantly in 500mg/kg/d DEHP group(P<0.05).In male rats, the levels of MDA、SOD、ACP of the testicles in 500mg/kg/d DEHP group increased significantly(P<0.05); no difference were found in serum oxidative stress.Conclusion: The oxidative stress of ovaries or testicles would be increased by DEHP exposure. And the serum may be not as sensitive as ovaries or testicles.Part Ⅲ The Effect of DEHP Exposure on Sex Hormone Level of Serum and Hippocampus in Infant RatsObjective: To study the effect of DEHP exposure on sex hormone level in serum and hippocampus in infant rats.Method: The levels of follicle stimulating hormone(FSH) and luteinizing hormone(LH) were assayed by ELISA.Result: In female rats, the level of serum LH of 500 mg/kg/d DEHP group decreased significantly(P>0.05); the level of serum E2 of 5 mg/kg/d DEHP group and the level of E2 in hippocampus of 0.5 mg/kg/d DEHP group both decreased significantly(P<0.05).In male rats, the level of serum FSH increased significantly in 50 and500mg/kg/d DEHP groups(P<0.05); the level of serum FSH increased significantly in5, 50 and 500mg/kg/d DEHP groups(P<0.05); the level of serum T increased significantly in 500mg/kg/d DEHP groups(P<0.05).Conclusion: These results suggest that the exposure to DEHP affected the serumlevels of sex hormones. E2 concentration in hippocampus of females decreased significantly while no significantly changes of T concentration in hippocampus of males were found.Part Ⅳ The Effect of DEHP Exposure on the Key Enzymes of Estradiol and Testosterone in Hippocampus of Infant RatsObjective: To study the effect of DEHP exposure on the key enzymes of E2 or T in hippocampus of infant rats.Method: The expressions of P450 arom, 3β-HSD, P450c17, P450 scc in hippocampus were detected by immunohistochemistry(IHC).Result: In female rats, the expression levels of P450 arom decreased significantly in 0.5 and 5mg/kg/d DEHP groups(P<0.05). The expression levels of P450c17 increased significantly in 0.5, 5mg/kg/d DEHP groups(P<0.05) while P450 scc only increased significantly in 0.5 mg/kg/d DEHP groups(P<0.05).Conclusion: The key enzymes of E2 or T in hippocampus may potentially be more sensitive to the low-dose DEHP exposure.