Histomorphometrical study of the testis in the desert Rodent,Gerbillus tarabuli, sexually immature and adult during the annual reproductive cycle

Abstract

Our interest in the testicular study of the desert rodent, Gerbillus tarabuli, would provide a better comprehension of the seasonality of spermatogenesis in rodents. We thus performed a biometric, histomorphometric and statistical analyses in Gerbillus tarabuli sexually immature and adult during the annual reproductive cycle (active and regressed states of gonadal activity). For that, fixed testes were embedded in paraffin. Sections were stained using the modified Heidenhain Azan and then were subjected to morphometric measurements at the light microscopic level. The biometric study revealed a positive correlation between the body weight and the maturity state only, with an average of 20.8 ± 2.92 g in sexually immature Gerbils, 37.40 ± 1.86 g in the sexually quiescent adults (p < .01) and 40.40 ± 2.98 g in the sexually active adults (p > .05), while the testes weight (sexually immatures = 0.02 ± 0.003 g, sexually quiescent adults = 0.13 ± 0.01 g; p < .001 and sexually active adults = 0.27 ± 0.01 g; p < .001) and the gonadosomatic index (sexually immatures = 0.09 ± 0.02%, sexually quiescent adults = 0.36 ± 0.04%; p < .01 and sexually active adults = 0.68 ± 0.07%; p < .01) varied according to the maturity state and as well as to the season in the adults. Through the histomorphometric study, the tubular diameter showed a continuous increase from sexually immature Gerbils (72.83 ± 7.57 μm) to sexually quiescent adults (99.45 ± 4.34 μm) p < .05 then to sexually active adults (182.58 ± 5.22 μm); p < .001, this is explained by the appearance of a large lumen after puberty in the quiescent (26.32 ± 1.28 μm); p < .001 and the enlargement of the seminiferous epithelium in actives (75.11 ± 1.81 μm); p < .001. Besides, the nucleo‐cytoplasmic ratio of Leydig cells (sexually immatures = 0.5 ± 0.02) diminishes significantly after puberty in the rest period (0.42 ± 0.03); p < .05 and then during the active period (0.24 ± 0.01); p < .001. These striking biometric and morphometric differences in Gerbillus tarabuli testis between sexually immature Gerbils, sexually quiescent and active adults, follow the photoperiod‐induced changes in endocrine and exocrine functions and prove that Gerbillus tarabuli is a useful model to study histo‐physiological relationships in the testis in order to develop a more complete understanding of spermatogenesis phenomenon.

Seasonal variations of testis anatomy and of G‐coupled oestrogen receptor 1 expression in Gerbillus gerbillus

“…In addition, the interstitial space was reduced. The results of the current work mirror those obtained in sympatric species ( Psammomys obesus, Gerbillus tarabuli and Gerbilliscus leucogaster ) (Gernigon‐Spychalowicz, 1992; Hamidatou Khati & Hammouche, 2021; Khammar, 1987; Menad et al, 2017; Muteka et al, 2018). Moreover, the changes observed in Leydig cells in our study, the increase of the nucleo‐cytoplasmic ratio and the reduction of cytoplasmic volume noticed during the resting season in Psammomys obesus and Gerbillus tarabuli , evince the inhibition of the metabolic activity of Leydig cells (Gernigon‐Spychalowicz, 1992; Hamidatou Khati & Hammouche, 2021).…”

“…In addition, the interstitial space was reduced. The results of the current work mirror those obtained in sympatric species (Psammomys obesus, Gerbillus tarabuli and Gerbilliscus leucogaster) (Gernigon-Spychalowicz, 1992;Hamidatou Khati & Hammouche, 2021;Khammar, 1987;Menad et al, 2017;Muteka et al, 2018). Moreover, the changes observed in Leydig cells Seasonal variations in the testicular activity in seasonal breeders have been documented in desert rodents (Psammomys obesus, Gerbillus gerbillus, Gerbillus tarabuli and Gerbilliscus leucogaster); testicular mass, testicular and plasma concentrations of testosterone decrease significantly during the resting season (Amirat et al, 1977;Boufermes et al, 2013;Gernigon-Spychalowicz, 1992;Hamidatou Khati & Hammouche, 2021;Khammar, 1987;Khammar & Brudieux, 1987;Muteka et al, 2018).…”

“…Seasonal variations in the testicular activity in seasonal breeders have been documented in desert rodents ( Psammomys obesus , Gerbillus gerbillus , Gerbillus tarabuli and Gerbilliscus leucogaster ); testicular mass, testicular and plasma concentrations of testosterone decrease significantly during the resting season (Amirat et al, 1977; Boufermes et al, 2013; Gernigon‐Spychalowicz, 1992; Hamidatou Khati & Hammouche, 2021; Khammar, 1987; Khammar & Brudieux, 1987; Muteka et al, 2018). In these cases, the interplay among histological compartments, hormonal levels and the regulation of receptors provides evidence that breeding is stimulated during a brief period when resources are available.…”

Advances in research on the biology of the desert rodent Gerbillus tarabuli: a review

“…Recently, a complete biometric and histomorphometric study of the testis in sexually immature animals and adults during the annual reproductive cycle was established by Hamidatou Khati and Hammouche. 46 Furthermore, the seminiferous epithelium cycle is studied, and 14 well-defined stages have been identified. 47 Within the testis, both hypothalamic gonadotropin regulators: Gonadotropin-releasing hormone (GnRH) and RFamide-related peptide-3 [RFRP-3—the mammalian ortholog of avian gonadotropin-inhibitory hormone (GnIH)] have been studied locally.…”