Objective To investigate the dynamic expression of Heat shock protein 70 (Hsp70) in the lungs and plasma of rats with pulmonary fibrosis induced by silicon dioxide (SiO2).Methods Forty-eight Wistar rats were randomly divided into the control group exposed to normal solution and group exposed to SiO2 (50 mg/ml) with intratracheal injection.Each group was divided into four subgroups.The animals of SiO2 group and control group were sacrificed and lungs were collected on the 7th,14th and 28th days after exposure,respectively.The left lung tissues were examined with the histopathologic HE s taining.The expression and localization of Hsp70 protein in the lung tissues were examined with western blot assay and immunohistochemistry,respectively.The expression levels of Hsp70 protein in the plasma were measured by ELISA.Results The expression of Hsp70 in lung tissues of SiO2 group increased on the 7th day and reached the peak value on the 14th day then decreased,but still was significantly higher than that of the control group,the expression of Hsp70 in plasma of SiO2 group still was significantly higher than that of the control group (P＜0.05).The maximum expression level of Hsp70 in plasma of SiO2 group on the 21st day after exposure was 0.216 ± 0.027 μg/ml.Conclusion The expression levels of Hsp70 protein in the lung tissues and plasma of the group exposed to SiO2 significantly increased,which were associated with the process of pulmonary fibrosis.It was suggested that Hsp70 protein may play an important biological role in the pulmonary fibrosis induced by SiO2.%目的 探讨热休克蛋白70( heat shock protein 70,Hsp70)在二氧化硅诱导的大鼠肺纤维化过程中的变化.方法 48只Wistar大鼠随机分成对照组和染尘组,每组24只,分别观察7、14、21、28d.染尘组经气管内灌注二氧化硅(50mg/ml),对照组予等剂量的生理盐水.HE染色观察病理学变化,蛋白免疫印迹( Western bolt)法和免疫组织化学法检测肺组织中Hsp70的表达与定位,双抗夹心ELISA检测血浆中Hsp70含量的变化.结果 染尘组染尘后7d肺组织中Hsp70含量升高,14d达到高峰,随后降低,但仍高于正常对照.染尘组14、21、28 d时血浆中Hsp70含量明显高于生理盐水对照组,差异有统计学意义(P＜0.05).染尘组血浆中Hsp70含量21d达到峰值[(0.216±0.027) μg/ml].结论 在染尘组大鼠肺组织和血浆中Hsp70含量均明显升高,并随肺纤维化进程出现先升高后降低的趋势,提示肺组织中Hsp70在二氧化硅诱导的肺纤维化过程中有重要的生物学作用.
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