Cell death patterns of the rat spermatogonial cell progeny induced by Sertoli cell geometric changes and Fas (CD95) agonist

Spermatogonial-Sertoli cell cocultures, prepared from sexually immature rat s (7-10 days old) and maintained for experimental purposes for a maximum pe riod of time of eight days, were used to determine whether Sertoli cell geo metry can influence spermatogonial cell growth, viability and differentiati on. We have found that when Sertoli cells are allowed to stretch, spermatog onial cell cohorts attached to Sertoli cell surfaces remain viable and exhi bit typical cell oscillatory movements with a maximal oscillation radial le ngth of 0.8 mu m throughout the duration of the experiments. However, sperm atogonial cell viability decreased when Sertoli cells were compelled to con tract by preventing cell spreading onto a non-adhesive substrate. A video-m icroscopy analysis of spermatogonial cells progenies cocultured with contra cted Sertoli cells revealed that conjoined members of the cohorts displayed a typical apoptotic sequence preceded by vigorous oscillatory cell movemen ts (maximal oscillation radial length: 1.5 mu m) followed by the release of apoptotic bodies and cessation of cell movements. This sequence of events occurred in a single cell. Upon completion of this sequence, another member of the cohort initiated the same cell death course until all members compl eted the cell death sequence. A similar apoptotic sequence was observed fol lowing addition of Fas (CD95/APO-1) antibody (ligand agonist) to the cocult ures, Fragmentation of the actin-containing cytoskeleton was observed by in direct immunofluorescence in apoptotic spermatogonial cell cohorts, indepen dent from the activating mechanism. We conclude that by forcing Sertoli cel ls to contract or by adding an apoptosis inducer to the cocultures, individ ual members of a spermatogonial cell cohort switch on a death (apoptosis) p rogram in a coordinated fashion. Dev Dyn 1999;214:361-371, (C) 1999 Wiley-L iss,Inc.