Previous exposure to Cyclosporine A and periodontal breakdown in rats

The aim of this study was to evaluate the influence of previous exposure to Cyclosporine A (CsA) on experimental periodontitis in rats.

Forty rats were divided into 4 groups: Control (CON); Cyclosporine A (CsA), which received daily doses of 10mg/kg CsA; Ligature (LIG), which received an insertion of a cotton ligature around the mandibular 1st molar at day 30; and Ligature and CsA (CsAL), which were treated with CsA and the cotton ligature. At day 60 of the experiment, animals were sacrificed, and groups were compared with regards to Alkaline Phosphatase (AP) activity, gingival overgrowth, periodontal bone support (PBS), bone resorption at furcation ligament area (LA) and TRAP+ cells. Data were analyzed by ANOVA/Tukey and Kruskal-Wallis and were considered to be statistically significant at 5% level.

CsA and LIG groups showed similar gingival area, which was higher than that in the CON and lower than in the CsAL group (p=0.001). The ratio between epithelial area and connective area for the CON group was similar to the CsA group and higher than that for the CsAL and LIG groups (p=0.0334). Mean percentage of PBS for the CON group was similar to that for the CsAL group and higher than that of the CsA and LIG groups (p=0.0007). No difference was observed regarding AP (p=0.2806) and TRAP+ cells (p=0.3995) among experimental groups. Mean values for LA of CON were similar to CsA, and both were statistically lower than the CsAL and LIG groups (p=0.0172).

Based on these results, we posit that previous exposure to CsA may influence gingival overgrowth, but not bone loss, in rats with experimental periodontitis.