ObjectiveTo verify the association between the Ddit3-Trib3-Akt signaling pathway and rat spermatogenesis by constructing an in vitro co-culture system of testis. MethodsTesticular tissue blocks from 20-25-day-old male rats were placed in an in vitro culture system， and the culture medium was replaced every 2 to 3 days. PCR was used to verify the expression of marker genes of various spermatogenic cells. RNA interference technology was employed to verify the correlation between the Ddit3-Trib3-Akt signaling pathway and rat spermatogenesis. ResultsThe co-culture system could be continuously cultured for more than 2.5 months in vitro. RT-PCR showed that specific marker genes of spermatogonia， spermatocyte and spermoblast were expressed. The RNA and protein expression of Trib3 and Akt changed after the knocking down of Ddit3 and Trib3， respectively. It demonstrated the existence of Ddit3-Trib3-Akt signaling pathway in rat spermatogenesis. ConclusionThe culture time of more than 2.5 months indicates that the culture system can temporarily maintain the proliferation and differentiation of stem cells， and simultaneously maintain and stabilize spermatogenesis in a simple system. The successful validation of the Ddit3-Trib3-Akt signaling pathway also confirms that this culture system can be used to study possible molecular mechanisms of spermatogenesis in vitro.

Objective To investigate the transcriptional and translational expression of Slitrk6 in rat spermatogene-sis.Methods The mRNA transcription level and translation level of Slitrk6 were detected by RT-qPCR and West-ern blot,respectively in testis of rats aged 2-65 days(repeat three times at each time point).Results The mRNA expression of Slitrk6 reached the highest on day 4 and day 10.SLITRK6 protein was continuously expressed during testis development in rats.Slitrk6 was found in human testis through PPI network.Conclusions Slitrk6 is potential-ly involved in mitosis and meiosis in spermatogenesis;The Slitrk6 may be one of the key genes in spermatogenesis.SLITRK6 protein is involved in mitosis and the transformation of round spermatids.The results lay a foundation for subsequent research on male infertility.

Objective:To investigate the damage effect of bisphenol A (BPA)on the testis tissue of adult mice, and to reveal the reproductive toxicity of BPA in the body of animal and mechanism.Methods:40 KM mice aged 8 weeks were randomly divided into control group (according to the weight ratio of corn oil gavage), low dose of BPA group (100 mg·kg-1BPA),moderate dose of BPA group (200 mg·kg-1 BPA),and high dose of BPA group (400 mg·kg-1 BPA).4 weeks laster,the testis tissue was taken.The apoptotic rates in the testis tissue were detected by flow cytometry;the distribution and expression of Fas and FADD were measured by immunohistochemistry.Results:Compared with control group,the apoptotic rate,the expression rates of Fas and FADD in testis tissue of the mice in low dose of BAP group had no changes (P>0.05),while the apoptotic rates in the testis tissue and the positive expressions rates of Fas and FADD in moderate and high doses of BPA groups were increased (P<0.05).Compared with low dose of BPA group,the apoptotic rates and the positive expression rates of FAS and FADD in tests tissue of the mice in moderate and high doses of BPA groups were significantly increased (P<0.05).Compared with moderate dose of BPA group,the apoptotic rate and the positive expression rates of FAS and FADD in testis tissue of the mice in high dose of BPA group was significantly increased (P<0.05).The overexpression of Fas and FADD was positively correlated to the apoptotic rate in testis tissue in moderate dose of BPA group (r=0.430,P<0.05;r=0.238,P<0.01)and high dose of BPA group (r=0.637,P<0.01;r=0.359,P<0.01).Conclusion:BPA with content dose can increase the apoptotic rates of cells in testis tissue and the expressions of Fas and FADD.BPA’s reproductive toxicity may be closely associated with the activation of Fas signal pathway and resulting in massive apoptosis.