Obata Fumiko, Yu Guannan, Ohta Haruka, Susuki Naoto, Shimazaki Mariko, Nishimura Saori, Hanai Miho
Department of Molecular Pathology, Graduate School of Medicine, University of Yamanashi.
Department of Nutrition and Life Science, Kanagawa Institute of Technology.
J Nutr Sci Vitaminol (Tokyo). 2020;66(1):86-90. doi: 10.3177/jnsv.66.86.
Nutrition and light-dark cycle influence rat testicular development. With 9% casein diet (low protein diet) under normal 12 h-12 h lighting cycles (9P), juvenile rat testes undergo normal growth. On the other hand, a low protein diet with constant darkness (D9P) results in a growth arrest of rat testes. Supplementation of cystine to the low protein diet under constant darkness (D9PC) had a tendency to increase testes weight, suggesting an improvement in growth suppression. Whether the growth suppression of testes in D9P is associated with suppression of spermatogenesis has not yet been shown. We aimed to determine the effect of a low protein diet and constant darkness with or without dietary cystine in testes using a histological technique. In the histological assessment, D9P testes showed a decreased number of seminiferous tubules with elongated spermatids, indicating a functional testicular defect in this group. However, cystine supplementation resulted in enhanced spermatogenesis versus control animals (D9PC vs. D9P) implying the importance of cystine to testicular development in this condition. Furthermore, serum testosterone concentration was increased in D9PC suggesting contribution of testosterone to ameliorate spermatogenesis. From these results, we conclude that cystine supplementation to a low protein diet under constant darkness promoted an increase in testosterone which in turn benefitted spermatogenesis.
营养和昼夜节律影响大鼠睾丸发育。在正常的12小时光照-12小时黑暗周期（9P）下，以9%酪蛋白饮食（低蛋白饮食）喂养时，幼年大鼠睾丸能正常生长。另一方面，在持续黑暗条件下的低蛋白饮食（D9P）会导致大鼠睾丸生长停滞。在持续黑暗条件下给低蛋白饮食补充胱氨酸（D9PC）有使睾丸重量增加的趋势，表明生长抑制有所改善。D9P中睾丸生长抑制是否与精子发生抑制有关尚未得到证实。我们旨在使用组织学技术确定低蛋白饮食和持续黑暗条件下，添加或不添加饮食胱氨酸对睾丸的影响。在组织学评估中，D9P组睾丸的生精小管数量减少，伴有伸长的精子细胞，表明该组存在功能性睾丸缺陷。然而，与对照动物相比，补充胱氨酸导致精子发生增强（D9PC与D9P相比），这意味着在这种情况下胱氨酸对睾丸发育很重要。此外，D9PC组血清睾酮浓度升高，表明睾酮有助于改善精子发生。从这些结果来看，我们得出结论，在持续黑暗条件下给低蛋白饮食补充胱氨酸可促进睾酮增加，进而有益于精子发生。
