| In order to reduce the aggressiveness of male mammalians and improve the growth rate and meat quality of meat livestock,these animals are often castrated at their early ages.In recent years,GnRH vaccine has been gradually used as an alternatives to surgical castration.Since GnRH and its receptors are expressed in immune system,the development of immune system may be affected in those animals immun immunized with GnRH vaccines.However,few references are available in this field till now.In this study,the effect of active immunization against GnRH on the thymus and spleen of SD rats were investigated.Seventy rats were randomly assigned into 2 groups: control(n = 35)and immunized(n = 35).Twenty-day-old rats were immunized with GnRH vaccine(immunized group)or 50% adjuvant(control group)and booster immunization was administered every 2 w(3 immunizations in total).Samples(including blood,testicle,thymus and spleen)were collected every 2 w from rats(5 immunized rats and 5 control rats)since the first immunization(seven collections in total)for the research.The results showed that: 1)GnRH immunization increased GnRH antibody titers and reduced testosterone concentrations(both P<0.05).2)The number of CD3+ cells increased after an initial decrease(P<0.05).The number of CD4+CD8-cells,CD4-CD8+ cells and CD4+CD8+ cells increased over time(P<0.05).The number of CD4+CD25+ cells reduced over time(P<0.05).3)Body weight did not differ significantly between the 2 groups;however,the relative weight of the testicle decreased(P < 0.05),and the relative weights of the thymus and the spleen increased(P < 0.05)over time.4)Serum concentrations of interleukin(IL)-2,IL-4,IL-6,IL-10,IL-17 and interferon-γ(IFN-γ)increased(P<0.05)over time.Similar changes in the mRNA levels of IL-2,IL-4,IL-6.IL-10,IL-17,IFN-γ,CD4,CD8,CD19 GnRH and GnRH receptor(GnRH-R)occured in thymus and spleen,and no significant difference in the expression of TNF-α and CD25 was found.Conclusion: GnRH immunization can increase immune ornan index,enchance the expression of immuno cell surface molecular markers and immune cytokines in the thymus,spleen and blood in rats. |
