POSITIVE CORRELATION BETWEEN BLOOD CYCLOSPORINE-A LEVEL AND SEVERITY OF GINGIVAL OVERGROWTH IN RATS

CYCLOSPORIN A IS A DRUG USED TO CONTROL REJECTION Of Organ transplanta tion and autoimmune diseases; however, it has also been implicated in gingival overgrowth. The present study investigates the relationship b etween severity of gingival overgrowth and blood cyclosporin A (CsA) l evels in Fischer rats treated orally with CsA. Thirty-six 15-day-old m ale rats were divided into six experimental groups and given powdered rat chow containing 0, 50, 100, 200, 300, and 400 mu g CsA/g diet ad l ibitum for 40 days. At the end of the 40-day treatment period, whole b lood samples were collected from each rat for assessment of CsA levels . The rats were then sacrificed and the gingival sulcus depth (pseudop ocket) around mandibular molars measured to estimate gingival overgrow th. The blood levels of CsA in rats increased with increasing amounts of CsA provided in their food. A 100% incidence in gingival overgrowth was induced in all the rats treated orally with CsA. The overgrowth w as more severe in buccal than in lingual gingiva. A significantly posi tive correlation was found between gingival sulcus depth and the blood CsA level (r(s) = 0.914, P < 0.0001; Spearman's correlation coefficie nt by rank). On histological examination, the overgrown gingiva consis ted of a thickened epithelial layer and an accumulation of subepitheli al fibrous connective tissue components without marked distortion of t heir proportion.