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Effect of active immunization against GnRH-I on the reproductive function in cat
Shudong Jiang1, Meizhen Hong1, Shiping Su1
1Anhui Provincial Laboratory of Animal Genetic Resources Protection and Breeding, College of Animal Sciences and Technology, Anhui Agricultural University, Hefei, Anhui, China.
Insights
Active immunization using maltose binding protein-gonadotropin releasing hormone I hexamer (MBP-GnRH-I6) effectively reduced reproductive function in cats. This method led to gonadal atrophy and lower hormone levels, indicating MBP-GnRH-I6 is a potent immunogen.
Area of Science:
- Veterinary Science
- Reproductive Biology
- Immunology
Background:
- Hormonal regulation of reproduction is crucial in domestic animals.
- Developing effective immunocontraceptive agents is a key area in veterinary research.
- Understanding the impact of immunization on feline reproductive physiology is important for population control and animal welfare.
Purpose of the Study:
- To investigate the efficacy of active immunization against maltose binding protein-gonadotropin releasing hormone I hexamer (MBP-GnRH-I6) in altering feline reproductive function.
- To assess the impact of MBP-GnRH-I6 immunization on gonadal size, hormone concentrations, and reproductive tissue morphology in cats.
Main Methods:
- Cats were actively immunized twice with MBP-GnRH-I6 at 16 and 20 weeks of age.
- Serum concentrations of testosterone and estradiol were measured using radioimmunoassay.
- Anti-GnRH-I antibody levels were determined by ELISA.
- Testicular and ovarian tissues were histologically examined.
Main Results:
- Immunized cats exhibited significantly lower testicular and ovarian weights and sizes compared to control groups (P < 0.05).
- Serum testosterone and estradiol concentrations were significantly reduced in immunized cats (P < 0.05).
- Histological examination revealed testicular atrophy with reduced spermatogenesis in males and suppressed follicular development in females.
Conclusions:
- Active immunization against MBP-GnRH-I6 effectively suppresses reproductive function in cats.
- MBP-GnRH-I6 acts as a potent immunogen, leading to gonadal atrophy and reduced gonadal hormone production.
- This immunization strategy shows promise as a method for non-surgical sterilization in cats.
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.
