Thioredoxin-interacting Protein Deficiency Protects Against Diabetes Induces Increase In Germ Cell Apoptosis And Oxidative Stress In Mice Testis

Objective:Thioredoxin-interacting protein(Txnip),also known as vitamin D3-upregulated protein,is a multifunctional protein involved in regulation of redox homeostasis and cellular metabolism.Txnip is a stress sensor and its expression can be induced by high glucose.A number of studies have suggested that diabetes impaired male testicular function in both humans and animals.Here,we tested the hypothesis that Txnip knockout mice are protected from diabetes-induced testicular damage.Methods:1.Immunohistochemistry,immunofluorescence,PCR and western blotting methods were employed to identify the expression of Txnip in mice testis.2.Txnip knock-out mice were generated using transcription activator-like effector nuclease(TALEN)technology.A diabetes model of male mice was induced by multiple low-dose STZ injections.The mice were randomly divided into four groups(n = 6): wild-type mice(WT),Txnip knoc-kout(KO),WT + STZ and KO + STZ group,The blood sugar was then measured daily using blood glucose tests strips and meter(ACCU-CHECK,Roche Diagnostics).Diabetic mice(WT)were confirmed by the levels of blood glucose measurement(?16.7 mmol/l).All mice were sacrificed after 60 d of treatment.Subsequently,testis and blood specimen were collected for further analysis.3.Immunohistochemistry and western blotting methods were employed to identify the expression of Txnip in Txnip knoc-kout mice testis.Testicular damage was evaluated by HE staining and terminal deoxynucleotidyl transferase dUTP nick-end labeling(TUNEL)assay.Further,the levels of malondialdehyde(MDA)and superoxide dismutase(SOD)of testis were also measured.Results: 1.The results of immunohistochemistry,immunofluorescence,PCR and western blotting revealed that Txnip was present in the Sertoli cells,Leydig cells and germ cells of mice testis.Further immunofluorescence staining indicated that Txnip protein was localized predominantly within the cytoplasm of TM4 Sertoli cells and TM3 Leydig cells.2.The results of immunohistochemistry and western blotting revealed that Txnip was absent in the testis of Txnip knock-out mice.Blood glucose levels of Txnip knock-out mice were significantly lower than those of wild-type mice.3.Testicular morphology results showed that STZ treatment induced significant pathological changes,increased testicular morphology damage,germ cell apoptosis,and decreased anti-oxidant capacity in testis of wild-type mice,however,these changes were absent,or markedly attenuated in Txnip knock-out mice.Conclusions: The study demonstrats that Txnip is expressed in mice testis,and is localized within the cytoplasm of TM4 Sertoli cells and TM3 Leydig cells.Txnip knock-out protects against diabetes-induced testicular damage by inhibiting germ cell apoptosis and decreasing oxidative stress,and Txnip inhibition maybe serve as a potential therapeutic approach.