1,25-(OH)2D3对肺纤维化大鼠中PI3K、AKT、mTOR表达的影响及其机制研究

摘要

Objective To observe the effect of 1,25-(OH)2D3 on expressions of PI3K, AKT and mTOR in rats with idiopathic pulmonary fibrosis (IPF), and to investigate its mechanism. Methods Ninety male SD rats were randomly divided into a model group, a treatment group and a control group (30 in each group). Bleomycin (5 mg/kg) was injected into the trachea of the rats to establish the model of pulmonary fibrosis in the model group and the treatment group, while the control group was injected with sterile physiological saline (200 μl for each). From the 2nd day, the rats in the treatment group received intraperitoneal injection of 1,25-(OH)2D3(2 μg/kg), and the rats in the model group and the control group were given the solvant (99.9% propylene glycol and 0.1% ethanol, 200 μl per rat) and sterile physiological saline (200 μl per rat) respectively by intraperitoneal injection, once every other day. Ten rats were sacrificed randomly on the 14th, 21st and 28th day in each group. The hydroxyproline content of the lung tissues of the rats in each group was measured. The mRNA and protein expression levels of PI3K, AKT and mTOR were tested by real-time PCR and immunohistochemistry, respectively. Results The hydroxyproline content of the lung tissues, the mRNA and protein expression levels of PI3K, AKT and mTOR were obviously increased in the model group and the treatment group compared with those in the control group on day 14, 21 and 28 (P < 0.05). However, all the above indicators in the treatment group were reduced significantly compared with those of the model group on day 14, 21 and 28 (P < 0.05). Conclusions The PI3K/AKT/mTOR pathway plays an important role in IPF. 1,25-(OH)2D3 has certain therapeutical effect on IPF, perhaps it plays a role through inhibiting the PI3K/AKT/mTOR signaling pathway.%目的 观察1,25-(OH)2D3对特发性肺纤维化(IPF)大鼠中PI3K、AKT、mTOR表达的影响,并探讨其对IPF的作用机制.方法 90只雄性SD大鼠随机分为模型组、治疗组及对照组,每组30只.模型组和治疗组按5 mg/kg的剂量气管内注射博来霉素,复制肺纤维化模型,对照组注入无菌生理盐水(200 μl/只).注射后第2天起,治疗组腹腔注射1,25-(OH)2D3(2 μg/kg),模型组和对照组分别腹腔注射1,25-(OH)2D3溶剂(200 μl/只)和无菌生理盐水(200μl/只),均隔天1次.各组于第14、21和28天分别处死10只,检测各组大鼠肺组织中羟脯氨酸的含量,实时聚合酶链反应(real-time PCR)和免疫组织化学方法分别从mRNA水平和蛋白质水平检测肺组织中PI3K、AKT、mTOR的表达.结果 模型组和治疗组大鼠肺组织羟脯氨酸的含量,PI3K 、AKT 、mTOR 3种基因的转录表达和蛋白质表达量,在第14、21和28天均高于对照组(P <0.05),且治疗组中的上述指标,在各时间又均低于模型组(P <0.05).结论 IPF的发生发展过程中,PI3K-AKT-mTOR通路具有重要作用,1,25-(OH)2D3对IPF有一定的治疗作用,其机制可能是通过抑制PI3K-AKT-mTOR通路发挥其治疗作用.