Expression of mRNAs of type 1 collagen and cytokin

环孢菌素A(CsA)和硝苯地平的显著副作用是诱导纤维性牙龈过度生长。本研究的目的是观察这些药物对20日龄含药和不含药(对照)饲料喂养的大鼠牙周组织中I型胶原代谢的影响。免疫组织化学分析显示，55天时，CsA和硝苯地平治疗组的牙龈结缔组织中I型胶原含量高于对照组。分别于第0、3、8、15、30、55天从下颌磨牙牙龈提取总RNA。逆转录-聚合酶链式反应(RT-PCR)定量分析发现，CsA组大鼠肝组织中I型胶原和胶原酶的表达逐渐降低，第55天分别为0d的0.4%和18.0%。在对照组中，I型胶原和胶原酶mRNAs的表达分别下降至19.7%和63.0%，表明CsA处理组这两种产物的表达均显著低于对照组。在硝苯地平组，这两种产物的表达也同样显著降低。用胶原包被的胶乳微珠，用流式细胞仪检测第8天和第30天牙龈成纤维细胞的胶原吞噬功能。CsA作用后第8天和第30天，牙龈成纤维细胞的吞噬细胞百分率分别为5.5%和9.0%。而对照组的成纤维细胞在第8天和第30天分别为53.8%和35.5%。硝苯地平作用30天的牙龈成纤维细胞含有12.6%的吞噬细胞。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。综上所述，这些结果表明，药物诱导的牙龈过度生长可能是由于I型胶原降解减少所致。

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.