Studies On Protective Effects And Mechanisms Of Nano-selenium Against Nickel-induced Testicular Injury And Apoptosis In Rats

Objective:The aim of this study was to explore the protective effects and potential mechanisms of Nano-Se on the NiSO₄-induced testicular injury and apoptosis in rat testes.Our finding will provide a new theoretical basis for the prevention and treatment of nickel reproductive toxicity.Methods:?1?Nano-Se colloidal solution was synthesized by novel laser abla-tion in liquid?LAL?and laser irradiation in liquid?LIL?methods.Meanwhile,the morphology,composition and size of Nano-Se were analyzed.?2?Then,forty adult male Sprague-Dawly rats were randomly divided into five groups:control group?saline?,NiSO₄ group?5 mg/kg NiSO₄?and three Nano-Se intervention groups?5mg/kg NiSO₄ combined with 0.5,1.0 and 2.0 mg/kg Nano-Se,respectively?.NiSO₄was administered intraperitoneally,whereas Nano-Se was given by oral gavage.All groups were treated for 14 consecutive days.?3?The rats were anesthetized with ether and sacrificed on day 15,and the testes were promptly removed.Hematoxylin and eosin?HE?staining was determined to observe histological changes in testes.?4?The content of malondialdehyde?MDA?and the activity of glutathione peroxidase?GPx?in testicular homogenate were measured by thiobarbituric acid?TBA?and colorimetric method,respectively.?5?The TUNEL assay was performed to evaluate the apoptosis in testes.?6?Immunohistochemistry was performed to detect the expression of the pivotal apoptosis factor?Caspase 3?in testicular tissues.?7?The expression levels of mitochondria apoptosis related genes and proteins?Bak,Bcl-2,Cytochrome c,Caspase 9 and Caspase 3?were analyzed by RT-qPCR and Western blot,as well as the expression levels of GRP78 and GADD153 involving in endoplasmic reticulum stress?ERS?were also detected.Results:?1?The stable and homogeneous red Nano-Se colloidal solution was obtained by LAL and LIL methods.The sample presented a regular spherical appearance and an average size was 52±12 nm.?2?Obvious pathological damage were observed in NiSO₄ group,which mainly manifested as the destruction of the spermatogonial tubules structure,disordered arrangement of spermatogenic cells at all levels,and significant decrease of the number of germ cells.However,abnormal testicular morphology and the seminiferous tubule structure were significantly improved after Nano-Se treatment.?3?Compared with control group,the MDA level elevated and GPx activity decreased in NiSO₄ group?P<0.05?,while Nano-Se markedly reduced MDA level and increased GPx activity?P<0.05?.?4?In the NiSO₄group,the apoptotic cells and positive expression level of Caspase 3 significantly increased in rat testes.Conversely,Nano-Se treatment remarkably decreased the number of apoptotic cells and reduced positive expression level of Caspase 3?P<0.05?.?5?Compared with control group,The mRNA and protein expressions of pro-apoptotic genes Bak,Cytochrome c and Caspase 9 were significantly upregulated,whereas the mRNA and protein expressions of anti-apoptotic gene Bcl-2 were significantly downregulated in NiSO₄-treated rats?P<0.05?.Also,the mRNA levels of GRP78 and GADD153 were upregulated in NiSO₄ group?P<0.05?.Nano-Se treatment significantly downregulated the Bak,Cytochrome c and Caspase 9 and upregulated Bcl-2 expression levels when compared with NiSO₄ group,whereas the protein expressions of GRP78 and GADD153 did not change obviously?P>0.05?.Conclusion:Nano-Se could improve NiSO₄-induced testicular injury and exert protective effect against NiSO₄-induced apoptosis;the possible mechanism may be mainly related to the regulation of mitochondrial apoptosis pathways.