Expression of mRNAs of type 1 collagen and cytokin

环孢菌素A（CsA）和硝苯地平的突出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日龄大鼠牙龈中1型胶原代谢的影响，这些大鼠喂食含或不含（对照）药物的粉状饲料。免疫组织化学分析显示，I型胶原蛋白更普遍的结缔组织中的CsA和硝苯地平治疗的牙龈比那些控制在第55天。在第0、3、8、15、30和55天分离来自下颌磨牙牙龈的总RNA。用逆转录聚合酶链反应（RT-PCR）定量分析CsA处理的大鼠的mRNA，发现I型胶原和胶原酶mRNA的表达逐渐减少，与0天相比，第55天分别减少0.4%和18.0%。在对照组中，I型胶原和胶原酶mRNA也分别下降至19.7%和63.0%，表明CsA处理组中这两种产物的表达与对照组相比显著降低。在硝苯地平治疗组，这两种产物的表达也明显减少。使用胶原包被的乳胶珠通过流式细胞术测量在第8天和第30天从牙龈分离的成纤维细胞的胶原吞噬作用。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。而来自对照的成纤维细胞在第8天和第30天分别含有53.8%和35.5%。从硝苯地平处理的牙龈中分离的成纤维细胞在第30天含有12.6%的吞噬细胞。因此，从CsA或硝苯地平治疗牙龈结缔组织中的吞噬细胞的比例显着减少。总之，这些结果表明，药物诱导的牙龈增生可能是由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.