A mitochondrial mechanism is involved in apoptosis of Robertsonian mouse male germ cells

Abstract

The aim of this study was to determine whether the intrinsic mechanism of apoptosis is involved in the death of germ cells in Robertsonian (Rb) heterozygous adult male mice. Testes from 5-month-old Rb heterozygous CD1!Milano II mice were obtained and compared with those from homozygous CD1 (2nZ40) and Milano II (2nZ24) mice. For histological evaluation of apoptosis, TUNEL labelling and immunohistochemistry were used to localise Bax and cytochrome c. Expression of calbindin D 28k (CB), an anti-apoptotic molecule, was also analysed by immunohistochemistry and immunoblotting. Testicular ultrastructure was visualised by electron microscopy. Morphology and cell associations were abnormal in the Rb heterozygous seminiferous epithelium. An intense apoptotic process was observed in tubules at stage XII, mainly in metaphase spermatocytes. Metaphase spermatocytes also showed Bax and cytochrome c redistributions. Mitochondria relocated close to the paranuclear region of spermatocytes. CB was mainly expressed in metaphase spermatocytes, but also in pachytene spermatocytes, spermatids and Sertoli cells at stage XII. The co-localisation of CB and TUNEL labelling was very limited. Sixty per cent of metaphase spermatocytes were apoptotic and calbindin negative, while 40% were calbindin positive without signs of apoptosis. Ten per cent of the Bax-and cytochrome c-positive cells were also calbindin positive. These data suggest that apoptosis of the germ cells in heterozygous mice occurs, at least in part, through a mitochondrial-dependent mechanism. Calbindin overexpression might prevent or reduce the apoptosis of germ cells caused by Rb heterozygosity, which could partially explain the subfertility of these mice. Reproduction (2008) 135 797-804

Expression of calbindin-D28k is inversely correlated with proapototic gene expression in hydrogen peroxide-induced cell death in endometrial cancer cells

“…The rate of apoptosis was significantly decreased in CaBP-28k-overexpressing pancreatic β cells treated with cytokines (19), and CaBP-28k overexpression protected osteoblasts against TNF-induced apoptosis through a mechanism involving the inhibition of caspase 3 activity (17). CaBP-28k also reduced the rate of apoptosis in germ cells in the Robertsonian heterozygous adult male mouse (60). Therefore, increasing intracellular CaBP-28k expression blocks apoptosis induced by different pro-apoptosis pathways.…”

Spermatogenesis in house mouse in a Robertsonian polymorphism zone

“…In fact, the existence of one pachytene checkpoint that arrests meiosis and induces cell elimination if the recombination or synapsis is altered has been postulated (Roeder & Bailis 2000, Merico et al 2003. Moreover, it has been observed that primary spermatocytes of Rb structural heterozygotes have alterations in the regulation of enzymatic activity (Hotta & Chandley 1982), qualitative differences in the protein patterns (Forejt 1982, Merico et al 2008, and longer prophase I (Redi et al 1985).…”

Local Injection of Mesenchymal Stem Cells Protects Testicular Torsion-induced Germ Cell Injury

“…Western blot analysis revealed that OFSCs abrogated the testicular torsion-induced caspase 3 ( Figure 2D) and bax ( Figure 2E) expression in the testis. apoptosis in germ cells [20]. It has already been established that torsion-detorsion increased the oxidative stress in testis which triggers apoptosis from the intrinsic pathway [2][3][4].…”