Calbindin D28k over-expression in hybrid mice might protect male germ cells from apoptosis

DÍAZ DE BARBOZA, G; PONCE, R; MERICO, V; RODRÍGUEZ, V; GARAGNA, S; TOLOSA DE TALAMONI, N.

Stresa-Lake Maggiore (Italia)

Simposio; 48th Symposium of the Society for Histochemistry; 2006

Universidad de Pavia (Italia)

It is well known that mammalian germ cells with structural rearrangements of karyotype show an increase in the death rate. Calbindin D28k (CB), a cytosolic protein which acts as a calcium buffer, has cellular protective functions in many tissues. In this work we evaluated the calbindin D28k (CB) capacity to protect mate germinal cells from apoptosis in mice with Robertsonian (Rb) rearrangements. Testis from adult mate mice with standard telocentric chromosomes (2n = 40, CDl), homozygous (2n = 24, Milan II) and heterozygous (2n = 24x40, hybrid) for Rb rearrangements were analyzed at different ages. CB expression was determined on transverse sections of the seminiferous tubules, employing immuno peroxidase technique with polyclonal antibody against CB. Apoptosis was studied via DNA fragmentation by the TUNEL assay. Hybrid mice have a larger number of apoptotic cells than the other two groups of mice. Apoptosis was mainly observed in cells from the stage XII. CB expression was also more intense in meiotic germ cells from the same stage in the hybrid mice, especially at 5 month old. Only 10% of germinal cells showed double staining of CB and TUNEL positive at 3 and 5 months old. CB expression in the germinal cells from CDl or Milan II mice was absent in the stage XII and it was very low (1-5 cells/ seminiferous tubule) in other stages from these mice. The results suggest that CB over-expression in the meiotic germinal cells from hybrid mice might occur to buffer intracellular calcium increase and to protect cells from apoptosis.