Apoptosis during spermatogenesis in the spotted ray Torpedo marmorata

Abstract

This article is a cytological and molecular investigation on the occurrence of apoptosis during spermatogenesis in Torpedo, a cartilaginous fish characterised by a typical cystic testis. Using DNA fragmentation and Bak gene expression, it demonstrated that germ cells undergo apoptosis only at the stages of spermatocyte and spermatid, and degeneration also involves Sertoli but not Leydig cells. In immature cysts, this cellular process probably occurs when the ratio of germ cells to the only Sertoli cell (SC) forming the spermatoblast changes. Apoptosis also takes place in mature cysts after sperm release to eliminate most of the SCs. Few of them, however, become cytoplasts and probably continue secreting androgens so as to control the final events of spermatogenesis, i.e., passage of spermatozoa through the ductus deferentes. Finally, the present investigation demonstrated that, in Torpedo testis, Bak mRNA is expressed during spermatogenesis, thus suggesting that the mitochondrial pathway might be active. This observation in one of the oldest vertebrate classes indicates that, in all vertebrates, the apoptotic process during spermatogenesis is conserved, contributing to testicular homeostasis.

Stage and season effects on cell cycle and apoptotic activities of germ cells and Sertoli cells during spermatogenesis in the spiny dogfish (Squalus acanthias)

“…McClusky, unpublished observations). Our findings, however, differ from those reported in the spotted ray, Torpedo marmorata, which show no stage-dependency and cell-type specificity of testicular apoptosis (Prisco et al 2003). Since a ZD has also been noted in each testicular lobe of the Atlantic stingray, Dasyatis sabina (Maruska et al 1996), and a ZD and stage-dependent premeiotic apoptosis seen in the little skate, Raja erinacea (L.M.…”

Testicular structure and spermatogenesis of Amazonian freshwater cururu stingray Potamotrygon cf. histrix

“…At the time of cell division, it was observed that within the same spermatocyst, there were spermatoblasts containing cells at different phases of cell division, thus resulting in the presence of different cell types within the same spermatocyst, with the presence of secondary spermatocytes and some spermatoblasts and spermatids within others. Prisco et al (2003) also identified different stages of cell differentiation in the same spermatogenic cyst in Torpedo marmorata and also among other elasmobranchs, such as Centroscymnus coelolepis and Centrophorus squamosus (Girard et al, 2000).…”

Assessment of the Effects of Bisphenol A on Dopamine Synthesis and Blood Vessels in the Goldfish Brain

“…BPA is widely found in aquatic environments and causes reproductive toxicity in fish, often resulting in abnormal testicular and ovarian development [16][17][18]28,29]. BPA has also been demonstrated to accumulate in various fish tissues, leading to pathological changes, including changes in the endocannabinoid system, changes in the ontogeny of the cortisol stress response, and energetic impairments [22,23,30].…”

“…Fish are often used to evaluate the health of aquatic ecosystems, in particular, physiological and biochemical changes in fish are considered biomarkers of environmental pollution [15]. Previous studies have suggested that BPA, as an analog of estrogen, may exert an estrogenic effect on fish gonad development and reproductive axis-related gene expression [16][17][18][19][20]. BPA also affects various biological processes in fish, including metabolism, individual cortisol stress responses, energy metabolism, muscle structure, motor behavior, and axonal growth, thereby affecting fish growth and development [21][22][23][24].…”