Spermatogonial morphology, kinetics and niches in hamsters exposed to short- and long-photoperiod

• Published in: International journal of andrology Vol. 32; no. 5; pp. 486 - 497
• Main Authors: do Nascimento, H.F, Drumond, A.L, de França, L.R, Chiarini-Garcia, H
• Format: Journal Article
• Language: English
• Published: Oxford, UK Oxford, UK : Blackwell Publishing Ltd 01.10.2009; Blackwell Publishing Ltd; Blackwell
• Subjects: Animals; Apoptosis; Biological and medical sciences; Cricetinae; Fundamental and applied biological sciences. Psychology; golden hamster; golden hamsters; Gynecology. Andrology. Obstetrics; high-resolution light microscopy; Kinetics; Male; Male genital diseases; Mammalian male genital system; Medical sciences; Mesocricetus; Mitosis; Photoperiod; spermatogonia; Spermatogonia - cytology; spermatogonial kinetics; spermatogonial niches; stem cell; Vertebrates: reproduction; spermatogonial kinetics; spermatogonial niches; Stem cell; Rodentia; high-resolution light microscopy; Photoperiod; Germinal cell; Male genital system; Vertebrata; Reproduction; Mammalia; golden hamster; Animal; Morphology; Spermatogonia; Hamster
• ISSN: 0105-6263; 1365-2605
• DOI: 10.1111/j.1365-2605.2008.00884.x

Previous studies have shown that under short photoperiod exposure spermatogenesis in golden hamster regresses leading to sexual inactivity. It is known that this regression is related to changes in somatic and germ cells (spermatocytes and spermatids). However, the photoperiod effects on spermatogonial biology have not been studied in detail yet. In this regard, this study was carried out to investigate the morphology, kinetics and niches of different spermatogonial types in golden hamsters under long- and short-photoperiod. Six spermatogonial generations such as type A undifferentiated (Aund), type A differentiating (A₁, A₂, A₃), intermediate (In) and type B spermatogonia were characterized, and were morphologically similar irrespective of the photoperiod exposure. The short photoperiod was inhibitory to Aund spermatogonia and preleptotene but had no effect on the number of differentiating (A₁ to B) spermatogonia. In golden hamsters exposed to stimulatory-photoperiod, the interstitial components were positioned mainly in triangular areas around the seminiferous tubules and, in this situation, the Aund spermatogonia were clearly positioned in niches (p < 0.05) in all stages studied. On the other hand, during the inhibitory-photoperiod where the seminiferous tubules have smaller diameter, the interstitial components were more homogenously distributed and the triangular areas were not clearly observed. In this case, the niches were identified only at stage VII (p < 0.05), although there was a trend of being positioned in niches area in all the stages studied. Thus, these findings suggest that the Aund spermatogonia location in the seminiferous epithelium and the niche position are directly related to the position of the interstitial components.