Effect of active immunization against GnRH‐I on the reproductive function in cat

Abstract

This study was designed to explore the effect of active immunization against maltose binding protein-gonadotropin releasing hormone I hexamer (MBP-GnRH-I6) on the reproductive function in cats. Each immunized cat was administered twice intramuscularly in the neck at 16 and 20 weeks old. The concentrations of the testosterone and estradiol and the level of anti-GnRH-I antibody in the serum were measured by radioimmunoassay and ELISA, respectively. The results showed that the weight and size of testicles and ovaries, and the concentrations of serum testosterone and estradiol in the immunized animals were lower than those of the control cats (P < 0.05), but that the levels of anti-GnRH-I antibody were significant higher compared to control animals (P < 0.05). Testicular tissues from the immunized male cats showed that seminiferous tubules were depauperate with the lumen relatively empty and that the differentiation of spermatogonia was not obvious. Tissues from the immunized female cats showed that the ovaries had many primordial follicles and primary follicles, but no secondary follicle was observed. These results showed active immunization against MBP-GnRH-I6 could make the gonads atrophy and reduce the concentrations of gonadal hormones, which suggested that MBP-GnRH-I6 was a very effective immunogen in the cat.

Effect of GnRH Active Immunisation on Reproductive Performance of Male Sprague Dawley Rats

“…In addition to its endocrine effects, GnRH influences the morphological aspects of animal growth and development. Jiang et al observed seminal tubular hypoplasia and reduced spermatogonial differentiation in immunised mice, confirming the profound morphological impact of GnRH-targeted immunisation [3]. Similarly, chitosan-adjuvant GnRH vaccines are associated with testicular atrophy and the onset of azoospermia, suggesting their effectiveness in inducing sterility [17].…”

“…This approach relies on vaccination against the gonadotropin-releasing hormone (GnRH) to inhibit reproductive functions [ 1 , 2 ]. GnRH, a pivotal neuropeptide synthesised and secreted by the hypothalamus [ 3 ], plays a central role in regulating the reproductive axis. Structurally, GnRH is a decapeptide with a specific sequence that is pyroglutamylated and amidated at its terminus, conferring enhanced biological activity and stability [ 1 ].…”

Effect of GnRH immunocastration on immune function in male rats

“…Tissues collected from the rats were fixed in 4% paraformaldehyde for 12 ~24 h at 4 °C, then were processed and stained with hematoxylin-eosin (HE) as Jiang et al described (41) The morphological changes and tissue structure of testis, thymus and spleen were observed under light microscope (BX51). Images were taken with Nikon Digital Sight DS-SMC camera.…”

Immunocontraception for Animals: Current Status and Future Perspective

“…GnRH vaccines have also shown success in female cats, inducing infertility for at least 20 months after two injections in one study, and for 5 months to 5 years after one injection in another study . A recombinant GnRH‐I maltose binding protein vaccine showed promising results in both male and female cats, although mating trials need to be performed . GnRH vaccines have also shown success in both male and female domestic horses, without any serious adverse effects …”