Expression of mRNAs of type 1 collagen and cytokin

环孢素A （CsA）和硝苯地平的主要副作用是诱导纤维性牙龈过度生长。本研究的目的是研究这些药物对20日龄大鼠饲粮中含或不含（对照）药物的牙龈1型胶原代谢的影响。免疫组织化学分析显示，在第55天，CsA和硝苯地平处理的牙龈结缔组织中I型胶原蛋白比对照组更普遍。分别于第0、3、8、15、30和55天分离下颌磨牙龈总rna。逆转录聚合酶链反应（RT-PCR）定量分析csa处理大鼠的mRNA，显示I型胶原和胶原酶mRNA的表达逐渐下降，与第0天相比，第55天分别下降0.4%和18.0%。在对照组中，I型胶原蛋白和胶原酶mrna也分别下降到19.7%和63.0%，表明csa处理组与对照组相比，这两种产物的表达均显著降低。在硝苯地平处理大鼠组，这两种产物的表达也同样显著降低。用胶原包被乳胶珠流式细胞术检测牙龈成纤维细胞第8天和第30天的胶原吞噬情况。从csa处理的牙龈中分离的成纤维细胞在第8天和第30天分别含有5.5%和9.0%的吞噬细胞。而对照组成纤维细胞在第8天和第30天分别为53.8%和35.5%。硝苯地平处理后第30天分离的成纤维细胞吞噬率为12.6%。因此，csa或硝苯地平处理的牙龈结缔组织中吞噬细胞的比例明显减少。这些结果表明，药物诱导的牙龈过度生长可能是由I型胶原降解减少引起的。

The prominent side effect of Cyclosporin A (CsA) and nifedipine is the induction of fibrous gingival overgrowth. The purpose of this study was to investigate the these drugs on type 1 collagen metabolism in the gingivae of 20-day-old rats feed with a powdered diet containing or lacking (control) drugs. Immunohistochemical analysis revealed that type I collagen were more prevalent in connective tissue of CsA- and nifedipine-treated gingivae than in those controls on day 55. Total RNAs from mandibular molar gingiva were isolated on days 0, 3, 8, 15, 30 and 55. Quantitative analysis of mRNA by reverse transcriptase polymerase chain reactin (RT-PCR), in CsA-treated rats, revealed a gradual decrease in expression of type I collagen and collagenase mRNAs, showing 0.4% and 18.0% on day55 compared with those on day 0, respectively. In the control groups, type I collagen and collagenase mRNAs also decreased to 19.7% and 63.0% respectively, indicating that the expression of both these products was significantly decreased in the CsA-treated group compared with controls. And in nifedipine-treated rat group, the expression of both these products was also significantly similarly decreased. Collagen phagocytosis of fibroblasts isolated from the gingiva on day 8 and 30 were measured by flow cytometry using collagen-coated latex beads. Fibroblasts isolated from CsA-treated gingiva contained 5.5% and 9.0% phagocytic cells on day 8 and 30, respectively. Whereas fibroblasts from controls contained 53.8% and 35.5% on day 8 and 30, respectively. And fibroblasts isolated from nifedipine-treated gingiva on day 30 contained 12.6% phagocytic cells. There were thus marked reductions in the proportion of phagocytic cells in connective tissue from CsA-or nifedipine-treated gingivae. Together these results indicate that drug-induced gingival overgrowth may be induced by decreased degradation of type I collagen.