Kataoka M, Shimizu Y, Kunikiyo K, Asahara Y, Yamashita K, Ninomiya M, Morisaki I, Ohsaki Y, Kido J I, Nagata T
Department of Periodontology and Endodontology, Tokushima University School of Dentistry, Tokushima, Japan.
J Cell Physiol. 2000 Mar;182(3):351-8. doi: 10.1002/(SICI)1097-4652(200003)182:3<351::AID-JCP5>3.0.CO;2-U.
Cyclosporin A (CsA) is used as an immunosuppressive agent and its prominent side effect is the induction of fibrous gingival overgrowth. The purpose of this study was to investigate the effect of CsA on the type I collagen metabolism in the gingiva of rats fed a powdered diet either containing or lacking CsA. Immunohistochemical analysis revealed that type I collagen was more prevalent in the connective tissue of CsA-treated gingiva than in those of control rats on days 15, 30, and 55 after the start of feeding. Total RNAs were isolated from mandibular molar gingiva on days 0, 3, 8, 15, 30, and 55. Quantitative analysis of mRNA by reverse transcriptase-polymerase chain reaction revealed that the CsA-treated groups showed a gradual decrease in expression of type I collagen and collagenase mRNAs, 0.4% and 18.0% on day 55 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, however, both mRNA expressions were significantly lower in the CsA-treated group than in the controls. An electron microscopic analysis of fibroblasts was performed to count the number of cells with collagen fibrils in the cytoplasm, a marker of phagocytosis of collagen by fibroblasts. The collagen fibrils were detected in 4.7% +/- 2.7% and 24.3% +/- 13.7% of fibroblasts in the overgrown gingiva treated with CsA rat for 8 days and 30 days, but in 57.0% +/- 5.3% and 81.3% +/- 9.2% of fibroblasts in the each control group gingiva, respectively. Furthermore, in vitro analysis was performed to measure the phagocytosis of cultured fibroblasts by flow cytometry using collagen-coated latex beads. Fibroblasts isolated from CsA-treated gingiva on day 8 and day 30 contained 5.7% +/- 0.6% and 9.9% +/- 1.5% phagocytic cells, whereas control fibroblasts contained 50.3% +/- 5.5% and 33.3% +/- 4.9% phagocytic cells, respectively. The inhibition rate of phagocytic activity was similar between in vivo and in vitro assays. These findings suggest that the decrease of the collagen degradation due to the lower phagocytosis and the lower collagenase mRNA expression are closely associated with the increase of type I collagen accumulation in CsA-treated rat gingiva.
环孢素A（CsA）用作免疫抑制剂，其突出的副作用是诱导牙龈纤维性过度生长。本研究的目的是调查CsA对喂食含或不含CsA的粉状饮食的大鼠牙龈中I型胶原代谢的影响。免疫组织化学分析显示，在开始喂食后的第15、30和55天，CsA处理的牙龈结缔组织中的I型胶原比对照大鼠的更普遍。在第0、3、8、15、30和55天从下颌磨牙牙龈分离总RNA。通过逆转录-聚合酶链反应对mRNA进行定量分析显示，CsA处理组的I型胶原和胶原酶mRNA表达逐渐下降，与第0天相比，在第55天时分别为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%，然而，CsA处理组的两种mRNA表达均显著低于对照组。对成纤维细胞进行电子显微镜分析，以计数细胞质中含有胶原纤维的细胞数量，这是成纤维细胞吞噬胶原的标志物。在用CsA处理大鼠8天和30天的过度生长牙龈中，分别有4.7%±2.7%和24.3%±13.7%的成纤维细胞检测到胶原纤维，但在每个对照组牙龈中分别为57.0%±5.3%和81.3%±9.2%。此外，进行体外分析，使用胶原包被的乳胶珠通过流式细胞术测量培养的成纤维细胞的吞噬作用。在第8天和第30天从CsA处理的牙龈中分离的成纤维细胞分别含有5.7%±0.6%和9.9%±1.5%的吞噬细胞，而对照成纤维细胞分别含有50.3%±5.5%和33.3%±4.9%的吞噬细胞。体内和体外试验中吞噬活性的抑制率相似。这些发现表明，由于吞噬作用降低和胶原酶mRNA表达降低导致的胶原降解减少与CsA处理的大鼠牙龈中I型胶原积累增加密切相关。
