Paraquat의 편측 기관지 주입에 의해 유발된 폐섬유화증에서 Cyclophosphamide와 Methylprednisolone의 투여에 따른 Endothelin-1의 발현의 변화

The Effects of Treatment with Cyclophosphamide and Methylprednisolone on Expression of Endothelin-1 in Unilateral Instillation of Paraquat-induced Pulmonary Fibrosis in Guinea Pigs

목 적 : 폐섬유화증 연구의 동물 실험 모델로 paraquat 중독이 자주 이용되고 있다. 본 연구에서는 paraquat로 유발된 폐섬유화에서 폐섬유화의 정도에 따른 Et-1의 변화를 면역조직화학적으로 관찰하고 스테로이드나 cyclophosphamide의 치료에 따른 Et-1의 변화를 관찰하여 폐섬유화과정에 Et-1의 역할을 밝히고자 하였다. 대상 및 방법 : 수컷 Hartley 기니픽을 4군으로 나누어 실험하였다. I 군은 paraquat를 투여하지 않은 군이었고, II 군용 paraquat를 폐에 주입한 후 cyclophosphamide와 methylprednisolone을 투여한 군이었고 III 군은 paraquat를 폐에 주입한후 methylprednisolone만 투여하였고, IV 군은 paraquat만 투입하였다. I 군을 제외한 나머지 군에서는 PE50 polyethylene tube를 이용하여 paraquat를 우측 폐로 주입하였다. 섬유화의 정도는 H-E와 Masson's trichrome 염색을 통해서 섬유아세포의 침윤정도와 교원질의 침윤정도로 판단하였고, Endothelin-1 면역조직화학염색을 통해서 세포의 활성도를 평가하였다. 각 군의 평균값은 median 값으로 표시하였고, 각 군간의 비교는 Kruskal-Wallis oneway analysis로 시행하였다. 결 과 : 1. Paraquat에 의한 폐 섬유화 Cyclophosphamide나 methylprednisolone의 치료로 paraquat에 의한 섬유아세포의 증식이 억제되었으나 통계학적 의미는 없었다. 교원질의 침윤은 cyclophosphamide와 methylprednisolone을 병합한 경우 paraquat만 투여한 군보다 의미있게 감소하였다(p<0.05). 2. Endothelin-1에 대한 면역조직화학염색 Paraquat의 투여로 발생된 폐섬유화증에 대한 치료의 종류에 따른 Et-1의 발현은 methylprednisolone의 단독 투여로도 폐포의 대식세포를 제외한 기관지 상피세포, 제2형 폐포세포, 혈관 내피세포 및 섬유아세포 등에서 Et-1의 발현이 감소하는 경향을 보였으며, cyclophosphamide와 methylprednisolone을병합한 군에서는 모든 세포에서 의미있게 Et-1의 발현이 감소하였고, 특히 폐포 대식세포와 섬유아세포에서는 methylprednisolone의 단독 투여한 III 군보다 의미있게 감소하였다(Table 2, p<0.05).

Background : The herbicide paraquat can cause severe lung injury and fibrosis in experimental animals. In this study we have investigated the changes in lung endothelin-1(Et-1) levels and immunohistochemical localization in relation to treatment with cyclophosphamide and methylprednisolone in paraquat induced pulmonary fibrosis in guinea pigs. Material and methods : 29 male Hartley guinea pigs were divided into 4 groups. Group I was normal control. Paraquat was instilled into the lung of guinea pig of group II, III and IV unilaterally. Group II was treated with cyclophosphamide and methylprednisolone. Group III was treated with methlprednisolone. Group IV was not treated. The degree of fibrosis was evaluated by H-E stains and Masson's trichrome stains and cell activity was assessed by Et-1 immunohistochemical stains. Statistical evaluation was performed using the Kruskawallis oneway analysis. Results : Paraquat induced an increase in numbers of fibroblasts and total amount of lung collagen in Group IV compared to the normal controls. There was no significant difference in total numbers of fibroblasts between any of paraquat instilled groups, but there was significant increase in total amount of collagen in Group IV compared to group II and III (p<0.05). The treatment of cyclophosphamide and methyprednisolone suppressed the growths of both fibroblasts and collagen, but this suppression was stastically significant only in the case of collagen Et-1 immunoreactivities of bronchial epithelium, type II pneumocytes, endothelial cells and fibroblast in group II and III were decreased compared to those in group IV. Conclusion : These results demonstrate that Et-1 is an important contributing factor in the pathogenesis of pulmonary fibrosis. Et-1 is synthesized and released by bronchial epithelium, Type II pneumocyte, endothelial cells, alveolar macrophages and fibroblasts. Especially they are associated with alveolar macrophage and fibroblasts. We conclude that combined therapy of cyclophosphamide and methylprednisolone are more effective in the control of Et-1 expression and collagen deposition.