Oral vaccination with inhibin DNA vaccine for promoting spermatogenesis in rats

The objective of the present study was to evaluate the effects of a novel Inhibin (INH) DNA vaccine (C500/pVAX-asd-IS) on the immune response, reproductive hormone levels, and spermatogenesis of rats. Forty healthy male rats were divided into four groups, and respectively immunized (thrice, 14 d apart) with 1×10⁸, 1×10⁹, and 1×10¹⁰ CFU of the recombinant inhibin vaccine (group C500/pVAX-asd-IS-L, C500/pVAX-asd-IS-M, and C500/pVAX-asd-IS-H) or 1×10¹⁰ CFU C500. P/N values increased after vaccination and differed (p <0.05) at 7 d, and sharply increased at 14 d following the booster vaccination (p <0.01); The weight and volume of testes in C500/pVAX-asd-IS groups were increased (p < 0.05) at decapitation, respectively; Histological evaluation showed that the number of spermatogenic cells in the lumen was increased, and the cytoplasmic remnants of sperms were allergy increased significantly compared with the control group. Oral vaccination with INH DNA reduced (P < 0.05) serum concentrations of INH B, enhanced serum concentrations of testosterone (T) and FSH. Furthermore, mRNA expressions of VIM and SMAD4 in the testes were increased in C500/pVAX-asd-IS-M and C500/pVAX-asd-IS-H groups (p < 0.05 or p < 0.01). The mRNA amount of INHβ-B in C500/pVAX-asd-IS-M group was greater than control group (p < 0.05).These results suggested that neutralization of endogenous INH through oral vaccination with INH DNA delivered by C500 strain successfully elicited a humoral immune response. INH gene immunization may have a positive effect on spermatogenesis and reproductive efficiency in male rats.