engleski

Modulatory effects of somatostatin on anti CD3 and dexamethasone induced apoptosis of thymocytes

Owing to the knowledge that numerous hormones and nerve-like fibres in the thymic tissue modulate the processes of thymic differentiation and maturation in this study we investigated the effects of somatostatin analogue SMS 201-995 on activation and steroid-induced apoptosis and maturation process of normal thymocytes. For this purpose the phenotypic analysis of CD4/8, CD3, CD54 and CD44 marker expression, as well as, cell cycle and DNA fragmentation of thymocytes were estimated 6, 18, 24, 36 and 72h after the treatment of mice or thymocytes with anti-CD3 antibodies or dexamethasone and SMS. The data have shown that SMS down-regulates the apoptotic process, induced by anti-CD3 antibodies (in vivo and in vitro), and potentiate the dexamethasone-induced cell death (in vivo). The effects were confirmed by slower or faster decrease in the percentage of T cells expressing CD4+CD8+and CD3high markers, respectively. In vitro SMS alone increased the percentage of TCR  / intermediate cells and delayed the down regulation of ICAM-1 expression on anti-CD3 triggered apoptotic cells, leaving unchanged the CD44 and ICAM-1 expression on DEX- triggered cells. The data point to influence of somatostatin on two mutually antagonistic pathways that regulate the processes of T cells commitment, maturation and elimination of autoreactive clones.

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nije evidentirano