The Study Of Zinc Deficiency Induced Spermatogenic Disords Through Affecting The Expression Of FAK And TGF-β1 In Mouse Testis

Objective: Zinc is an essential trace element,about 2-3 grams in the human body.Although zinc content in the body is very low,it is involved in more than 300 different biological processes,including DNA transcription,protein translation,cell proliferation,cell differentiation and cell apoptosis.Zinc deficiency refers to the decrease in zinc content in the body due to low zinc intake or abnormal metabolish.In 2012,the World Health Organization reported that about one-third of the world’s population is deficient in zinc,and nearly 30% of adult males in China also have varying degrees of zinc deficiency.Zinc deficiency can lead to slow development,mental retardation,low immune function,etc.Zinc also plays a vital role in the male reproductive system.Spermatogenesis refers to the formation process of sperm in the testis,including spermatogonia cell division and proliferation,spermatocyte meiosis,and spermatids deformation in three consecutive stages of cell division and differentiation.Zinc is involved in the spermatogenesis process and plays an important role in spermatogenesis.Zinc deficiency can also cause spermatogenesis disorders,but the exact mechansim is largely unclear.Therefore,we used the zinc-deficient CD-1 mice model to further investigate the morphological effects of zinc deficiency on the testis and epididymis of mice and the possible mechanism of zinc deficiency leading to spermatogenesis disorders.Methods:Four-week-old CD-1 male mice randomly divided into zinc deficiency group(ZD group)(N=20)and control group(N=20).Low zinc diet(0.85PPM)was used in ZD group,and normal zinc diet was used in control group.All mice drank deionized water and were maintained in stainless steel cages which were washed with 0.5% EDTA.After feeding for five weeks,testicular and epididymal specimens were taken and then the experiment was started.1.The concentration of zinc in testicular tissues of ZD group and control group was determined by atomic absorption spectrophotometry(AAS).2.Morphological changes of testis and epididymis in ZD group and control group were observed bt HE staining.3.H1T2 and TRA54 antibodies were used for dual immunofluorescence staining to detect the properties of exfoliated cells.4.Western Blot was used to detect the expression of ZO-1,FAK,TGF-β1,TGF-β2,TNF-α and Par6 in the testis of ZD group and control group.Results:1.The concentration of zinc in testis tissue of ZD group was 140.59±16.22ug/g by atomic absorption spectrophotometry.The concentration of zinc in testis tissue of control group was 218.44±31.92ug/g.The concentration of zinc in testis tissue of ZD group was significantly lower than control group(P<0.05).2.The testicular tissue structure was normal in the control group by HE staining.The seminiferous tubules were dense and the seminiferous epithelium was intact.All level of spermatogenic cells at all levels was clear and ordered.In the ZD group,the testicular seminiferous epithelium was degenerated,and the number of spermatids was reduced,especially the elongating and elongated cells.Vacuoles appeared in the cytoplasm of Sertoli cells.The seminiferous tubules were occlusive.The number of abnormal seminiferous tubules was increased.Exfoliated cells could be seen in the abnormal tubules and the caput,corpus and cauda of the epididymis in the ZD group.However,no exfoliated cells were found in the control group.3.Results of H1T2 and TRA54 antibodies dual immunofluorescence staining showed that the exfoliated cells in the ZD group were stained,which might be round spermatids that could not continue to mature.4.Western blot results showed that the levels of FAK and TGF-β1 in the ZD group were lower than those in the control group(FAK: P < 0.05,TGF-β1: P < 0.01),while the expression levels of ZO-1,TGFβ-2,TNF-α,Par6 were not significantly different(P > 0.05).Conclusion: Zinc deficiency could cause the morphological changes in mice testes.For example,the testicular seminiferous epithelium was degenerated,and the number of spermatids was reduced.Vacuoles appeared in the cytoplasm of Sertoli cells.The seminiferous tubules were occlusive.The number of abnormal seminiferous tubules was increased.At the same time,the testicular round spermatids could not continue to mature and cause exfoliated.FAK and TGF-β1 might play essential roles in the testicular pathological changes induced by zinc deficiency.