Effect of intra-testicular melatonin injection on testicular functions, local and general immunity of a tropical rodent Funambulus pennanti

Abstract

Local antigonadotrophic action of melatonin in testes has never been correlated with local and general immune status of any rodent. Intra-testicular injection of melatonin (2.5 μg/50 μl) for 10 days (MI-10D) and 20 days (MI-20D) was given to young adult male of Funambulus pennanti and testicular androgen receptor (AR), androgen binding protein (ABP) expression, 3β-hydroxysteroid dehydrogenase (3β-HSD) activity, and Mel1aR expression in thymus was checked along with general immune parameters. Further, immunohistochemical localization of Mel1aR in testes was done. Decreased AR, ABP expression, testes weight, 3β-HSD activity, testosterone level, and spermatogenesis but increased Mel1aR expression in thymus, immunoreactivity in testes, and testicular macrophages following injection was noted. Lymphatic tissue weight, leukocyte, lymphocyte count, lymphocyte proliferation in spleen, thymus, plasma melatonin, and IL-2 level increased in a duration-dependent manner following intra-testicular injection. Intra-testicular injection of melatonin decreased steroidogenesis by enhancing the primary effect of melatonin on Leydig cell endocrine function. Along with reduced circulatory testosterone production, an increase in testicular as well as general immunity was observed in a duration-dependent manner. Therefore, a local participation of melatonin in testes of F. pennanti to control testicular androgen production is suggested.

Melatonin Protects the Heart, Lungs and Kidneys from Oxidative Stress under Intermittent Hypobaric Hypoxia in Rats

“…However, in the aforementioned studies melatonin did not have any effect with the doses used in contrary to other reports where melatonin had a protective role in testis and spermatogenesis of rats subjected to intermittent hypobaric hypoxia (Hartley et al, 2009;Bustos-Obregón et al, 2010;Vargas et al, 2011);Ahmad & Haldar (2010) as well as hamsters and rats, where melatonin seems to act directly on Leydig cells to suppress testosterone release in vitro. When administered orally at 10 mg/kg bodyweight, melatonin has been described as a counteracting substance for testis and spermatogenesis damage in rats subjected to intermittent hypobaric hypoxia (Vargas et al, 2011).…”

UVB irradiation severely induces systemic tissue injury by augmenting oxidative load in a tropical rodent: Efficacy of melatonin as an antioxidant

“…The MT1 receptor expression pattern in the spleen showed significant stimulation in melatonin treated group as was previously noted [17] and was down-regulated in the UVB irradiated squirrels. The loss of normal cellular physiology due to the peroxidation of membrane lipids could be one of the reasons for the suppressed receptor expression since MT1 is associated with the cell membrane.…”

“…The spleen being a lymphoid organ has an extensive repertoire of lymphocytes and hence is under strong influence of melatonin which is immune-stimulatory by nature [17]. The results of our study showed a significant increase in the TLC in the melatonin administered squirrels and that pertains to the immune-stimulatory property of melatonin [28].…”

“…The Indian palm squirrel is a seasonal breeder whose reproductive and immune responsiveness is regulated by photoperiod and concentration of melatonin in circulation [17]. Hence the animal model proved suitable for the present objective.…”

“…Western blot analysis was performed following the method of Ahmad and Haldar 2010 [17]. Tissues were dissected out and lysed in RIPA buffer (1% (v/v) Igel CA-630, 0.5%(w/v) sodium deoxycholate, 0.1% (w/v) sodium dodecyl sulfate (SDS) in phosphate-buffered solution (PBS) containing aprotonin and sodium orthovanadate).…”