沙利度胺对肺纤维化大鼠肺组织中c-jun氨基末端激酶及α-平滑肌肌动蛋白表达的影响及意义

Effects and significance of thalidomide on c-jun amino acid terminal kinase and α-smooth muscle actin expression in rats with pulmonary fibrosis

目的观察沙利度胺在大鼠肺纤维化中的干预作用及对磷酸化c-jun氨基末端激酶(p-JNK)及α-平滑肌肌动蛋白(α-SMA)表达的影响,进一步分析沙利度胺在肺纤维化过程中可能的作用机制。方法将54只健康雄性Wistar大鼠随机分为对照组、模型组、沙利度胺组,每组各18只,于气管内滴注博莱霉素注射液制备肺纤维化模型,对照组给予气管内滴注0.9%氯化钠注射液。沙利度胺组于造模当日起给予沙利度胺(100mg/kg)灌胃,对照组和模型组给予等量0.9%氯化钠注射液,每日1次。各组分别于第7、14、28天随机处死6只大鼠,取肺组织行苏木素-伊红(HE)染色和Masson染色,碱水解法测大鼠肺组织羟脯氨酸(Hyp)含量,免疫组织化学法测肺组织中p-JNK蛋白及α-SMA的表达。结果模型组第7天时肺泡炎症明显,第28天时可见明显纤维化改变;随着时间的推移,羟脯氨酸含量呈逐渐上升趋势,第28天时含量最高;p-JNK蛋白及α-SMA的表达较对照组明显增加。沙利度胺组与模型组比较,肺泡炎症及纤维化程度均有所减轻;第14、28天时Hyp含量有所降低,p-JNK蛋白及α-SMA的表达有所减少(P<0.05);模型组α-SMA与p-JNK蛋白含量呈正相关。结论沙利度胺可减轻博莱霉素所致大鼠肺纤维化的程度,其机制可能是通过抑制p-JNK蛋白的活化及α-SMA的表达实现的。

Objective To study the effects of thalidomide on pulmonary fibrosis and expression of phosphory- lated c-jun amino acid terminal kinase （p-JNK） and a-smooth muscle actin （ot-SMA） in rats, and to further explore the underlying mechanisms of the therapeutic effects. Methods Fifty-four healthy male Wistar rats were randomly as- signed to control （n=lS）,,model （n=18） and thalidomide treatment group （n=18）, respectively. The pulmonary models were established via intratracheal injection of bleomycin （BLM）, while normal saline was administered in the control group on day 1. The thalidomide treatment group received thalidomide intragastric injection （100 mg/kg）, while the re- maining groups were treated with an aliquot of normal saline intragastric injection once daily. Six rats in each group were randomly sacrificed on days 7, 14 and 28, which entailed extraction of the lung tissues for haematoxylin-eosin and Masson staining. The content of hydroxyproline （Hyp） in the lung tissues was detected by alkaline hydrolysis technique, and p-JNK protein and a-SMA expression was assessed via immunohistochemistry assay. Results The model group evidenced significant alveolitis on day 7 and marked pulmonary fibrosis on day 28. The content of HYP increased gradually with time and culminated on day 28. The expression of p-JNK protein and a-SMA was signifi- cantly higher than that in control group. Compared with model group, alveolitis and pulmonary fibrosis were ameliorat- ed in the thalidomide treatment group, which showed reduced levels of Hyp and attenuated expression of p-JNK pro- tein and a-SMA （all P〈0.05） on days 14 and 28. There was a significant positive correlation between p-JNK protein and a-SMA expression in model group. Conclusion Thalidomide may ameliorate bleomycin-induced pulmonary fi- brosis in rats via inhibition of p-JNK protein activation and a-SMA expression.