Study On The Phenomenon And Mechanism Of Intergenerational Injury In Testis Of Adult Male Mice After DEHP Exposure

Di-(2-ethylhexyl)phthalate(Diethylhexyl phthalate,DEHP)is an industrial estrogen-like chemical that has weak estrogenic activity and is widely used in many consumer products.They can diffuse throughout the matrix and can be readily leached into the environment.Its toxic effects have been widely appreciated by people.The existing study show that DEHP can cause various aspects of toxicity such as nerve,liver,kidney,heart and embryo development,and its toxicity to the male reproductive system is more sensitive than females.Humans are exposed to phthalates via skin contact,consumption and inhalation.To date,it has been demonstrated that DEHP exposure can cause multiple reproduction damage in males.Mechanisms of reproductive toxicity induced by phthalates included spermatogenesis,cholesterol biosynthesis,testosterone production,epigenetic modification of oxidative stress genes.DEHP-induced male reproductive damage can be transgeneration inherited,when endocrine disruptors introduce epigenetic changes during early development.They permanently alter the epigenome in the germ line,and these changes can be transmitted to subsequent generations.This study is to evaluate the phenomenon of intergenerational injury repair on adult male mice testis of F1-F3 generation induced by DEHP exposure and the mechanism of damage repair.In the present experiment,the reproductive injury model was established by gavage from GD 9.5 to GD 15.5 of the pregnancy mice(DEHP was 675 mg/kg/day).We detected the changes in phenotype,hormone levels,histological level,the protein expression levels in PI3 K singnal pathway and the cell apoptosis of testis.F1-F3 generation male mice testes were taken for 112 days,and the body weight,testis coefficient,and anogenital distance of the mice were recorded.The sperm quality of the mice was analyzed,including sperm motility,sperm deformity rate,and expression levels of Pyk2.Histological changes in testicular tissue of mice were detected by HE staining,and the levels of FSH and LH in the serum of male mice were detected by radioimmunoassay.Western blot was used to detect the expression level of related proteins in the PI3 K signaling pathway associated with cell proliferation in F1-F3 mice,and TUNEL was used to detect the apoptosis of mouse testicular cells.We found compared with the control group,1.body weight and AGD was significant reduced in F1 generation and testis coefficient was decreased in F1 and F2 generation.2.Sperm motility was significant reduced and sperm deformity was higher in F1-F3 generation.The expression level of Pyk2 protein was significantly decreased in F1-F2 generation.However,it was significantly increased in F3 generation.3.In DEHP group of F1 mice,the gaps between the testicular seminiferous tubules increased.The numbers of spermatocytes became lesser,cracks and vacuoles appeared in the testicular seminiferous tubules of DEHP group.Drop of spermatids and abnormally colored cells,enlargement of intercellular space and disorderly arranged sperm cells were also observed.The damage was reduced during transgeneration inherited.4.Exposure of DEHP resulted in a decrease of LH levels in both F1 and F3 generations.There was no significant difference of FSH levels between the F1-F3 generations.5.DEHP exposure resulted in the up-regulation of IGF-1R protein expression,down-regulation of PTEN and IRS-1 protein expression levels in the PI3 K signaling pathway in F1 and F2 generations.There was no significant difference in F3 mice.6.The number of spermatogenic apoptosis cells was no significantly difference in F1-F2 mice.However,apoptosis cells were reduced in testis of F3 mice.In summary,exposure to DEHP during pregnancy can resulted in testicular reproductive injury,and the injury was repaired during transgeneration inherited.The mechanism of damage repair may be 1.Increase cell proliferation by affecting PI3 K signaling pathway.2.Affecting the spermatogenic cell apoptosis.In the process of transgeneration,the damage was gradually repaired.It may be through a self-regulation to restore the toxic effects.In this study,the transgenerational injury repair and the mechanism of damage repair caused by DEHP exposure were explored.It provides a theoretical reference for the further study of male reproductive damage and infertility caused by the exposure to DEHP.