Active immunisation against pregnenolone reduces testicular steroidogenesis and GnRH synthesis in rabbits

Active kisspeptin DNA vaccines oral immunization disrupt mRNA hormone receptors expression in ram lambs

To evaluate the efficacy of oral immunization with active kisspeptin DNA vaccine on the expression of hormone receptor mRNA. For this study, ten 56-day-old Hu breed ram lambs were randomly assigned to the treatment and control groups (n = 5). Treatment Experimental group received C500/pKS-asd and the control group received C500/pVAX-asd (aspartate-β semialdehyde dehydrogenase orally on days 0, 28, and 56, and blood samples were taken at each immunization interval (14-day) and tissues samples were collected at the end of the experimental period (day 98). The collected samples were stored in the refrigerator at -20 °C and liquid nitrogen, respectively, for laboratory examination. Total RNA was extracted from samples using TRIzol reagent and quantitative real-time polymerase chain reaction (QPCR) was used to quantify the levels of KISS1, G protein-coupled receptor-54 (Kiss1r), and gonadotrophin-releasing hormone (GnRH) mRNA in the hypothalamus. Levels of luteinizing hormone receptor (LHR) and luteinizing hormone beta (LHβ) mRNA, and follicle-stimulating hormone receptor (FSHR) and follicle-stimulating hormone beta (FSHβ) mRNA in the testes and pituitary were analyzed, respectively. Further, gonadotropin-releasing hormone receptor (GnRHR) mRNA expression level in the pituitary was measured. Moreover, the Kiss1r concentration level in the blood was measured using an indirect ELISA. The concentration of Kiss1r in the blood was lower in the treatment group than in the control group (p < 0.05). The levels of testicular FSHR and LHR mRNA were significantly lower in the treatment group (p < 0.05) when compared to the control group. Furthermore, the treatment group's levels of hypothalamic KISS1, Kiss1r, and GnRH mRNA were significantly lower (p < 0.05) than the controls. LH, FSH, and GnRHR mRNA expression in the pituitary were also significantly lower in the treatment group (p < 0.01 and p < 0.05, respectively). These findings imply that oral immunization with active kisspeptin DNA vaccine suppresses hormone receptor mRNA expression in the ram lambs.

Effect of immunological castration of male pigs on morphological and functional con-dition of the testicles

Changes in the priorities of the treatment of animals in the conditions of intense technology of production of livestock products are based on the necessity of wellbeing of animals. Therefore, there is a need of search for and broad introduction of generally accepted alternatives to surgery, which would use modern means of castration, particularly immunocastration. The study presents morpho-functional substantiation of practicability of using immunological castration in the conditions of industrial production of pork. At the same time, we studied immunological castration using Improvak on the morphological and physiological condition of the testicles of male pigs. The testosterone level was determined using radioimmunologic method after 2, 4, 6, 8 weeks of immunological and surgical castrations, and also in intact boars of the control group. During the slaughter, we selected biopates of the testicles in immunological castrates and pigs of the control group for histological examination. The testosterone level 2 weeks after castration was the lowest in the animals castrated using Improvak. This indicator gradually increased, and after 8 weeks was higher than in the surgically castrated pigs. In the latter, the level of testosterone gradually decreased for 8 weeks, and did not significantly change in non-castrated pigs. The last stages of spermatogenesis in immunocastrates were inhibited after the second vaccination. As a result of immunological castration, the interstitial tissue of the testicle underwent changes. Between the tubules, a spreading of the loose connective tissue was observed. Leydig cells lost hyper chromaticity of the cytoplasm and typical polygonal profile, and their functional potential decreased. This fact was confirmed by the changes in the Hertwig’s ratio. In particular, we observed decrease in the value of the nuclear-cytoplasmic ratio. There were also a time shift of mitotic cycle, low degree of differentiation of spermatogonia and rupture of the course of the subsequent stages of spermatogenesis. However, there occurred multiplication of primary spermatogonia, single cellular divisions, and in the ductus deferentes, there could be found single spermatids. Some of them formed specific cellular groups of rounded and elliptic shapes in the seminiferous tubules. These structures were absent in the testicles of the control animals. Microstructural changes in the swine after injecting Improvak were characterized by deficiency of Leydig cells, indicating absence of the normal hormonal background, as confirmed by the results of the study of testosterone level. The epithelium-spermatogenic layer was underdeveloped, and the lumens of the tubules were in some places filled with generations of spermatocytes. In some places, meiosis was observed, which also indicates insignificant functioning of the testicles. Vaccination with Improvak caused atrophy of the testicles in swine and decrease in their functional condition, allowing it to be recommended it for broader application as an alternative to surgical castration.

Effect of active immunization using a novel GnRH vaccine on reproductive function in rats

To investigate the effect of gonadotropin-releasing hormone 2-multiple antigen peptide (GnRH2-MAP) on reproductive function. In our study, 20-day-old male rats (n = 90) were randomly allocated to one of three treatment groups: GnRH2-MAP immunization, GnRH2 immunization, and non-immunized control groups. The immunized animals were administered three doses of GnRH2-MAP or GnRH2 vaccines from 0 to 6 weeks at 2-week intervals. The control group only received oil adjuvant. Blood and right testis samples were collected, and the left testis was weighed and its volume was measured at 0, 2, 4, 6, 8, 10 and 12 weeks after the first immunization. The serum antibody titer and testosterone concentration were determined by ELISA, and the right testis samples were collected for histological analysis. The results revealed that the serum of vaccinated rats elicited a significantly higher antibody titer and a lower T concentration compared with the control group two weeks after the first immunization (P < 0.05), but the highest antibody titer and lowest T concentration were found in animals treated with GnRH2-MAP (P < 0.05). The second immunization resulted in a significant decrease in testicular weight and volume (P < 0.05) in both immunized groups compared to the control, but these values were significantly lower in the GnRH2-MAP group than in the GnRH2 group. Furthermore, seminiferous tubules revealed more significant atrophy in the GnRH2-MAP group than in the GnRH2 group, and no sperm were observed in rats of the GnRH2-MAP group. Thus, GnRH2-MAP may be an effective antigen and a potential immunocastration vaccine with higher effectiveness.