Gelatinases and Extracellular Matrix Metalloproteinase Inducer Are Associated With Cyclosporin‐A‐Induced Attenuation of Periodontal Degradation in Rats

Background: The present study aims to examine the inhibitory effect of cyclosporin‐A (CsA) on periodontal breakdown and to further explore the correlations of CsA‐induced attenuation of periodontal bone loss with the expressions of gelatinases (i.e., matrix metalloproteinase [MMP]‐2 and MMP‐9) and extracellular matrix metalloproteinase inducer (EMMPRIN). Methods: Forty Sprague‐Dawley rats were randomly divided into four groups: 1) control; 2) CsA; 3) ligature (Lig); and 4) ligature plus CsA (Lig + CsA). The CsA group received 10 mg ⋅ Kg−1 ⋅ d−1 CsA for 8 days. The Lig group received silk ligature on selected molars. The Lig + CsA group received silk ligature and CsA treatment. The inhibitory effects of CsA on the ligature‐induced periodontal breakdown was examined with microcomputed tomography (micro‐CT) and histometric analyses to analyze the amount of attachment loss, crestal bone loss, connective tissue attachment, and the surface area with inflammatory cell infiltration. The effects of CsA on ligature‐induced expressions of gelatinases and EMMPRIN in gingival tissues were examined with Western blotting and zymography, respectively. Results: By micro‐CT and histology, the Lig + CsA group had significantly more periodontal breakdown than the control and CsA groups but less periodontal breakdown than the Lig group. Consistent results were found for the expressions of gelatinases and EMMPRIN among the groups demonstrating that the Lig + CsA group had significantly less gingival protein expression of gelatinases and EMMPRIN than the Lig group. Conclusions: CsA inhibited the expressions of gelatinase MMPs and EMMPRIN and partially prevented the periodontal breakdown in ligature‐induced experimental periodontitis. The CsA‐induced attenuation of periodontal bone loss was strongly correlated positively with the expressions of MMP‐2, MMP‐9, and EMMPRIN in gingiva.