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目的研究血管紧张素Ⅱ受体拮抗剂缬沙坦对肺纤维化模型的干预作用及其可能的机制。方法60只Wistar大鼠采用随机数字表法随机分成3组,每组20只:(1)缬沙坦组,经气管插管灌注博莱霉素(BLM)诱导肺纤维化,随后每日用缬沙坦16mg/kg灌胃进行干预;(2)模型组,气管内灌注用BLM,灌胃用生理盐水;(3)对照组,气管内灌注和灌胃均用生理盐水。各组动物于气管内灌注后第7、14、28、42天分别处死5只。取肺组织经苏木精-伊红、Masson胶原染色及测定羟脯氨酸浓度来评价治疗效果。用免疫组化及原位杂交方法分别检测转化生长因子β(TGF-β)蛋白和肝细胞生长因子(HGF)mRNA在肺内的表达。用酶联免疫吸附测定(ELISA)法检测HGF蛋白在大鼠肺组织的含量。结果缬沙坦组肺泡炎程度在第14、28、42天分别为(0·88±0·12)、(0·79±0·21)、(0·75±0·17)分,低于同期模型组的(2·05±0·25)、(1·38±0·12)、(1·19±0·11)分,差异均有统计学意义(P均<0·01);缬沙坦组肺纤维化程度在第7、28、42天分别为(0·28±0·03)、(1·74±0·18)、(1·91±0·09)分,也低于同期模型组的(0·45±0·10)、(2·08±0·32)、(2·77±0·15)分,差异均有统计学意义(P均<0·05);缬沙坦组肺组织羟脯氨酸含量在第14、42天分别为(1·08±0·13)、(1·39±0·20)μg/mg·pro,低于同期模型组的(1·45±0·19)、(2·19±0·37)μg/mg·pro,差异均有统计学意义(P均<0·01);缬沙坦组肺组织中TGF-β蛋白表达在早、晚期分别为2·27±0·30、2·05±0·18,均低于同期模型组的3·99±0·43、2·71±0·46,差异均有统计学意义(P均<0·05)。缬沙坦组HGFmRNA表达在早、晚期分别为1·61±0·20、0·52±0·19,均高于同期模型组的1·98±0·23、0·28±0·14,差异均有统计学意义(P均<0·05);缬沙坦组蛋白含量在早、晚期分别为(203±18)、(129±20)pg/ml,均高于同期模型组的(260±21)、(100±20)pg/ml,差异均有统计学意义(P均<0·05)。结论缬沙坦能减轻BLM诱导的大鼠肺纤维化,有可能通过抑制TGF-β和促进HGFmRNA的表达而实现。
Objective To investigate the intervention effect of angiotensin Ⅱ receptor antagonist valsartan on pulmonary fibrosis model and its possible mechanism. Methods Sixty Wistar rats were randomly divided into three groups (n = 20): (1) valsartan group, intratracheal instillation of bleomycin (BLM) induced pulmonary fibrosis, and then daily Valsartan 16mg / kg intragastric intervention; (2) model group, intratracheal instillation of BLM, intragastric administration of saline; (3) control group, tracheal perfusion and gavage with saline. Animals in each group were sacrificed on the 7th, 14th, 28th and 42nd days after intratracheal instillation respectively. Pulmonary tissue was harvested for hematoxylin-eosin, Masson collagen staining and hydroxyproline concentration to evaluate the therapeutic effect. Immunohistochemistry and in situ hybridization were used to detect the expression of transforming growth factor-β (TGF-β) and hepatocyte growth factor (HGF) mRNA in the lung. The content of HGF protein in rat lung tissue was detected by enzyme linked immunosorbent assay (ELISA). Results The level of alveolitis in the valsartan group was (0.88 ± 0.12) days, (0.79 ± 0.21) days and (0.75 ± 0.17) points on the 14th, 28th, and 42nd days respectively, There were significant differences between the model group (2.05 ± 0.25), (1.38 ± 0.12) and (1.19 ± 0.11) points in the same period (all P <0.01) ; The degree of pulmonary fibrosis in valsartan group was (0.28 ± 0.30) days, (1.74 ± 0.18) days and (1.91 ± 0.09) points respectively on the 7th, 28th and 42nd days, (0.45 ± 0.10), (2.08 ± 0.32) and (2.77 ± 0.15) points in the model group at the same period, the differences were statistically significant (P <0 · 0 05). The content of hydroxyproline in the lung tissue in the valsartan group was (1.08 ± 0.13) and (1.39 ± 0.20) μg / mg · pro respectively on the 14th and 42nd days, lower than that of the same period (1.45 ± 0.19) and (2.19 ± 0.37) μg / mg · pro in model group were significantly different (all P <0.01); in the valsartan group The expression of TGF-βprotein was 2.27 ± 0.30 and 2.05 ± 0.18 in the early and late stages respectively, which were all lower than the control group (3.99 ± 0.43.771 ± 0.46) The differences were statistically significant (P <0.05). In the early and late valsartan groups, the expression of HGF mRNA was 1.61 ± 0.20 and 0.52 ± 0.19 respectively, both higher than that of the model group at the same period (1.98 ± 0.23,0.28 ± 0.14 , Respectively (all P <0.05). The contents of valsartan in the early and late stages were (203 ± 18) and (129 ± 20) pg / ml, (260 ± 21) and (100 ± 20) pg / ml, respectively (all P <0.05). Conclusion Valsartan can attenuate pulmonary fibrosis induced by BLM in rats, possibly by inhibiting the expression of TGF-β and promoting the expression of HGF mRNA.