Effect of cyclosporin [A] administration and withdrawal on the mesenteric lymph nodes in albino rats

ABSTRACT

The present study investigated the histological changes induced in the mesenteric lymph nodes of albino rats by short-term cyclosporin A [CsA] administration and to determine the reversibility of these changes after CsA withdrawal. Eighteen adult male albino rats were randomly allocated into 3 groups; each of 6 rats. Control rats received a daily subcutaneous [s.c.] injection of olive oil at a dose of 1 ml/kg body weight [b.wt.] for 5 days. Control rats were sacrificed either 24 hours or one week after the last injection. Rats from CsA-treated group received a daily s.c. injection of CsA at a dose of 15 mg/kg b.wt. for 5 days. Rats were sacrificed 24 hours after the last injection. Rats from CsA-withdrawal group received a daily s.c. injection of CsA at a dose of 15 mg/kg b.wt. for 5 days. Rats of this group were sacrificed one week later. The results showed that CsA administration induced decreased cellularity of the mesenteric lymph nodes with decrease of CD3 positive T cells, CD57 positive cells and CD20 positive B cells. In contrast, CD68 positive macrophages increased. The germinal centers of lymphoid follicles were enlarged with a thin mantle. Numerous tingible-body macrophages were found in the germinal centers with multiple apoptotic bodies giving the starry-sky appearance of the germinal centers of the follicles. These histological changes showed regression or complete resolution with withdrawal of CsA administration