Active immunization with inhibin DNA vaccine promotes spermatogenesis and testicular development in rats

The objective of the present study was to investigate the potential role of immunization against INH on testicular development, serum reproductive hormone (FSH, LH and T) concentrations, testicular biochemical indexes (GGT, ALP, ACP, LDH, α-neutral glucosidase and carnitine) and testicular cell apoptosis in rats. Forty healthy male rats were randomly divided into four groups (n = 10 per group), and respectively immunized with 0.5 mL of C500/pVAX-asd-IS-L (108 CFU/ mL), C500/pVAX-asd-IS-M (109 CFU/ mL), C500/pVAX-asd-IS-H (1010 CFU/ mL) or C500 (1010 CFU/ mL) (thrice with an interval of 2 weeks). P/N values increased after vaccination and differed (p < 0.05) at 1 week and sharply increased at 2 weeks following the booster vaccination (p < 0.01); P/N values indicated that the immune response was induced and production of anti-INH antibodies in rats; Immunization of INH vaccines enhanced serum concentrations of T and FSH, while reduced LH concentrations (p < 0.05); The testis weight, volume, testis coefficient, epididymal weight, sperm count in the epididymis, and the sperm deformity results indicated that INH gene vaccine immunization could promote testicular development and enhance sperm production rate in rats. After immunization of INH gene vaccines, GGT activity was markedly increased, but ALP, LDH and α-neutral glucosidase activities were observably reduced (p < 0.05). Furthermore, flow cytometry results demonstrated that the apoptosis rate of the testicular cells was extremely increased in the C500/pVAX-asd-IS-M group (p < 0.01). These findings illustrate a functional cross-link between FSH, T, LH and spermatogenic markers via inhibin to maintain spermatogenesis. INH immunization may have a positive effect on spermatogenesis and testicular development in male rats.