Abstract
The thymus is known to play a vital part in the development and maintenance of the immune system. This study investigated the effects of the compound, Di-n-octyl-tin dichloride [DOTC], upon the thymus and the consequences of the DOTC-induced thymic injury upon immunocompetence. Oral exposure of PVG rats to DOTC produced a marked loss of thymic weight observed 4 days after commencement of treatment. The toxic effects of DOTC were observed to be primarily restricted to the thymus, however, a gradual decrease in the numbers of lymphocytes in the blood was observed subsequent to DOTC induced thymic weight loss. Insight into the mode of action of DOTC upon the thymus was obtained by investigating some factors which might have influenced the extent and reversibility of DOTC-induced thymic injury. Age appeared to have a considerable effect upon DOTC-induced thymic injury and reversibility, whereas adrenalectomy prior to treatment did not alter the extent or nature of thymic damage. Investigations into the consequences of DOTC-induced thymic injury upon the immune system demonstrated a decrease in polyclonal T-cell activation as measured by mitogenic blastogenic responsiveness and in allogeneic reactivity as measured by the mixed lymphocyte response. There was no significant alteration in T-cell dependent antibody production to a systemically administered antigen. The effects upon the immune system appeared to be limited in both extent and degree and were more comparable to those generally observed after adult thymectomy than those documented after administration of immunosuppressive drugs.