Preparation And Observation Of Immune Effect Of GnRH6 And FSHR DNA Vaccines

In order to reduce the aggressiveness of male stray animals and control their amount,animals are often castrated at their early ages.However,it may cause infection and stress reaction in stray animal that fail to meet animal welfare.In recent years,DNA immunocastration vaccine has been proved to inhibit sex steroids and gamatogenesis effectively resulting in infertility.In the present study,c DNA encoding GnRH hexamer(GnRH6)and part of FSHR gene is inserted into p EGFP-N1 respectively and the plasmids are emulsified with adjuvant.The effect of the DNA vaccines were demonstrated in juvenile and adult male mice.Exp.1 Active immunization against GnRH and FSHR on the functional integrity of reproduction in juvenile male miceKunming white mice at the age of 20 days were randomly allocated to four groups(n=42): p EGFP-N1(group C),p EGFP-N1-FSHR(group F),p EGFP-N1-GnRH6(group G)and p EGFP-N1-FSHR + p EGFP-N1-GnRH6(group FG).The immunization procedure was as follows: the first immunization was performed at the age of 20 days,and the enhanced immunization was performed at an interval of one week,with a total of 3 immunization times.Starting from the first immunization,7 mice in each group were executed at 0,1st,2nd,3rd,5th and 7th week,respectively.Testis were collected for histological observation and blood was collected for the detection of serum lever of antibody and testosterone.The results were as follows: 1)Compared to the control group(group C),the weight of mice in experimental groups(group F,G and FG)increased stably during the whole period of the experiment(P>0.05).The antibody level of FSHR reached the peak at the 5th week and then decreased.The antibody level of GnRH increased from the first immunization to the end of the experiment(the 7th week).The testosterone concentrations of experimental groups significantly decreased at 3rd,5th and 7th week after the first immunization(P<0.01).Compared to the control group,the transverse and longitudinal diameters of testes in experimental groups had no significant changes,and the testicular indexes of group G and group FG significantly decreased at 2nd and 3rd week after the first immunization,respectively(P<0.05).Histological observation showed that the cells in the convoluted seminiferous tubule of testis in group F,group G and group FG were sparser than those in group C,and the amount of spermatogenic cells decreased,but the spermatogenic cells at each development stage could be observed.Exp.2 Active immunization against GnRH and FSHR on the functional integrity of reproduction in adult male miceKunming white mice at the age of 6～8 weeks were randomly allocated to four groups(n=10): p EGFP-N1(group C),p EGFP-N1-FSHR(group F),p EGFP-N1-GnRH6(group G)and p EGFP-N1-FSHR + p EGFP-N1-GnRH6(group FG).After three times of immunization,male mice mated with female mice together to empty the sperms in the epididymis.The motility of sperm in epididymis of mice in group F and G were significantly decreased(P<0.05),the sperm motility and motility of FG mice were significantly decreased(P<0.01);Histological observation showed that the number of spermatogenic cells in the lumen of testis of mice in all experimental groups decreased,and the spermatogenic cells were sparse,especially in group F and FG.The spermatogenic tubules were atrophied,the lumen wall was empty,and there was no sperm in the lumen.Conclusion: Active immunization against GnRH6 and FSHR in juvenile and adult male mice with DNA vaccines could produce corresponding antibodies,which can reduce the testosterone concentration of serum in mice,decrease spermatogenic cells and block spermatogenesis.