miR-223通过抑制NLRP3防护小鼠急性放射性肺损伤

MiR-223 protects mice from acute radiation-induced lung injury by inhibiting NLRP3

目的研究miR-223通过抑制NLRP3对小鼠急性放射性肺损伤的防护。方法将40只雌性C57BL/6 J小鼠,按随机数表法将小鼠分成4个组:健康对照组、单纯照射组、照射+miR-223组和照射+阴性对照(NC)组,每组10只。其中3个照射组给予15 Gy X射线全肺单次照射,照射+miR-223组和照射+NC组自照射前1 d开始至照射后14 d,隔天尾静脉注射10 nmol miR-223 agomir或agomir-NC。照射后第14 d取肺组织标本,HE染色观察病理变化,免疫组织化学法观察IL-1β和IL-18的定位和表达,实时荧光定量PCR检测miR-223和NLRP3的表达,Western blot检测NLRP3和Caspase-1的表达,ELISA检测肺组织中IL-1β和IL-18的表达。结果辐射导致小鼠肺组织内miR-223表达下降和NLRP3的表达升高,给予miR-223 agomir可以抑制NLRP3的升高,同时减轻肺部炎症。实验结果显示,与单纯照射组相比,miR-223可以减轻小鼠肺组织的急性炎症反应。使得肺组织中IL-1β和IL-18表达下降(t=10.16、6.00,P<0.05)。肺组织NLRP3 mRNA表达下降(t=3.22,P<0.05)。Western blot结果显示,与单纯照射组相比,照射+miR-223组的NLRP3,Caspase-1蛋白表达下降(t=12.47、4.95,P<0.05)。Elisa结果也表明,在照射+miR-223组中炎症因子IL-1β和IL-18表达下降(t=8.22、8.47,P<0.05)。结论miR-223通过抑制NLRP3的表达,抑制炎症因子IL-1β和IL-18的分泌,减轻炎症反应,对急性放射性肺损伤具有保护作用。

Objective To investigate the radioprotective function and its mechanism of miR-223 in acute radiation-induced lung injury in mice.Methods Forty female C57BL/6 J mice were randomly divided into healthy control group,irradiation group,irradiation plus miR-223 group and irradiation plus NC group.Radiation groups were exposed with a single dose of 15 Gy of 6 MV X-rays delivered by a linear accelerator.The mice in drug group were administered by tail vein injection with miR-223 agomir or agomir-NC every other day from 1 d before irradiation to 14 d after irradiation.The lung tissue samples of mice were taken at 14 d post-irradiation.The pathological changes were observed by HE staining.The localization and expressions of IL-1β and IL-18 were observed by immunohistochemistry (IHC).Real-time PCR was used to detect miR-223,but NLRP3 mRNA expression in lung tissue.Western blot was used to detect the protein expressions of NLRP3 and Caspase-1,and ELISA assay was used to detect the expressions of IL-1β and IL-18 in lung homogenate.Results Radiation decreased the expression of miR-223,but increased the expression of NLRP3 in lung tissue.Administration of miR-223 agomir inhibited the expression of NLRP3 and attenuated lung inflammation.HE and IHC staining showed that miR-223 reduced the acute inflammatory response and the expressions of IL-1β and IL-18 in lung tissue compared with irradiation group (t=10.16,6.00,P<0.05).The expressions of NLRP3 and Caspase-1 protein in lung tissue of irradiated plus miR-223 group was lower than that in the irradiation alone group (t=12.47,4.95,P<0.05).ELISA assay also showed a decrease of inflammatory factors IL-1β and IL-18 in lung tissue homogenate of the irradiation plus miR-223 group (t=8.22,8.47,P<0.05).Conclusions MiR-223 effectively reduces the secretion of radiation-induced inflammatory factors IL-1β and IL-18 by inhibiting the expression of NLRP3 in lung tissue of mice,and thus has protective effect on radiation-induced lung injury.