BACKGROUND AND OBJECTIVE: Studies have shown that bacterial plaque and the associated gingival inflammation increase the severity of gingival overgrowth induced by cyclosporine-A (CsA). This in vitro study aimed to evaluate the effect of CsA on the activities of MMPs from the co-culture of human gingival fibroblasts and U937 macrophages in the presence or absence of Porphyromonas gingivalis lipopolysaccharide (LPS). MATERIAL AND METHODS: Activities of pro-MMP-2, MMP-2 and pro-MMP-9 in the supernatants of independent cultures and co-cultures were examined by zymography. RT-PCR was selected to evaluate the expression of mRNA for membrane type-1 (MT1) MMP in the co-cultures. RESULTS: Activities of MMPs in the co-cultures were significantly greater when compared with any of the independent cultures. Lipopolysaccharide significantly increased the MMP activities in a dose-dependent manner in the co-cultures, whereas CsA inhibited these activities. In the presence of both CsA and LPS, the MMP activities inhibited by CsA could still be observed in the co-cultures. In the individual cultures, in contrast, the CsA-inhibited MMP activities, in the presence of LPS, were minimally detected. The mRNA expression of MT1-MMP was significantly enhanced after LPS treatment; however, this enhancement was inhibited by CsA. CONCLUSION: This study demonstrated that, in co-cultures of human gingival fibroblasts and U937 macrophages, CsA could inhibit MMP activities in the presence of P. gingivalis LPS. It might be part of the underlying reason for the persistent overgrowth of gingiva seen when bacterial plaque and local inflammation are present during CsA therapy.
BACKGROUND AND OBJECTIVE: Studies have shown that bacterial plaque and the associated gingival inflammation increase the severity of gingival overgrowth induced by cyclosporine-A (CsA). This in vitro study aimed to evaluate the effect of CsA on the activities of MMPs from the co-culture of human gingival fibroblasts and U937 macrophages in the presence or absence of Porphyromonas gingivalislipopolysaccharide (LPS). MATERIAL AND METHODS: Activities of pro-MMP-2, MMP-2 and pro-MMP-9 in the supernatants of independent cultures and co-cultures were examined by zymography. RT-PCR was selected to evaluate the expression of mRNA for membrane type-1 (MT1) MMP in the co-cultures. RESULTS: Activities of MMPs in the co-cultures were significantly greater when compared with any of the independent cultures. Lipopolysaccharide significantly increased the MMP activities in a dose-dependent manner in the co-cultures, whereas CsA inhibited these activities. In the presence of both CsA and LPS, the MMP activities inhibited by CsA could still be observed in the co-cultures. In the individual cultures, in contrast, the CsA-inhibited MMP activities, in the presence of LPS, were minimally detected. The mRNA expression of MT1-MMP was significantly enhanced after LPS treatment; however, this enhancement was inhibited by CsA. CONCLUSION: This study demonstrated that, in co-cultures of human gingival fibroblasts and U937 macrophages, CsA could inhibit MMP activities in the presence of P. gingivalisLPS. It might be part of the underlying reason for the persistent overgrowth of gingiva seen when bacterial plaque and local inflammation are present during CsA therapy.