The Effect Of Gingivitis On Cyclosporine A-induced Gingival Overgrowth

Objective: To study the effect of cyclosporine A (CsA) , lipopolysaccharide (LPS) on cultured human gingival fibroblasts(GFs) and the effect of gingivitis on the rat with CsA-induced gingival overgrowth.Methods: Part 1. Human GFs were cultured using a routine method of tissue culture, then cells were identified by the methods of morphology, immunocytochemistry and MTT colorimetric assay. Part 2. Cells from the 4th passage to the 8th were transfered in DMEM containing 800ng/mlCsA,100ng/mlLPS,800ng/mlCsA +100ng/mlLPS. Cell proliferation was assessed utilizing MTT assay and TGF-β1 secreted in cell supernatant was measured by ELISA . Part 3. 18 SD rats were randomly divided into three groups. All experimental rats were subjected to placement of an orthodontic wire around the cervix of the first right maxillary molar. Each group's histological examination was made at week 1,2,4 to determine the time of gingivitis occur. Part 4. 34 SD rats were randomly divided into control group, ligation group, drug group and ligation+drug group. The latter two groups were received CsA daily by gastric feeding. After 9 weeks the rats were sacrificed. The morphological examination was made and the histological change with HE staining was observed. TGF-β1 level in serum was detected by ELISA.Result: 1 .The success rate of primary culture of human GFs was up to 80%. The cells were spindle-shaped, a positive reaction to antibodies against vimentin and type I collagen. 2. The cells had no morphological changes after drug exposure. CsA stimulated the cell proliferation and secretion of TGF-β1; LPS had the opposite effect ; the combine effect of CsA and LPS distinctly increased the proliferation and the secretion of TGF-β1. 3. Given orthodontic wire ligatured around the cervix of molar could induce experimental periodontitis. Histological examination showed that gingivitis occurred at week 1 and periodontitis occurred at week 4. 4. After 9-week CsA intake, remarkable weight loss and gingival overgrowth were found in the test rats, while those rats preexisted gingivitis showed more severely . TGF-β1 level in CsA-exposed rats'serum was higher than that in untreated ones, but ligation did not affect TGF-β1 level.Conclusion: 1. CsA and LPS have synergistic action in cell proliferation and TGF-β1 secretion. 2. Given orthodontic wire ligatured around the cervix of teeth can successfully induce experimental periodontitis in rats. The gingivitis will occur at week 1. 3. CsA-induced gingival overgrowth will be more apparent in the presence of inflammation. TGF-β1 may be a risk factor for developing gingival overgrowth.