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 agomirNC 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.

Objective: To investigate the effect of ubiquitous mitochondrial creatine kinase 1(CKMT1) on the sensitivity of human nasopharyngeal carcinoma cell line CNE-1 to DDP. Methods: CNE-1 cells were transiently transfected with CKMT1 overexpression (CKMT1) or empty vector (EV). The growth curve and DDP IC50 were developed by MTT assay, plate clone formation assay was performed by gradient concentration of DDP treatment, cell cycle and apoptosis were detected by flow cytometry, levels of apoptosis related protein Bax/Bcl-2/C-PARP and the transcription factor p-STAT3-Tyr705 were detected by Western Blot. Results: The transfection efficiencies of CKMT1 and EV were more than 90% with a higher proliferation rate in the CKMT1-transfected cells. However, the CKMT1-transfected cells had a DDP IC50 of 2.76 μmol/L, which was significantly lower than that of 4.60 μmol/L in the EV-transfected cells (P<0.01). With the treatment of certain concentration of DDP, the CKMT1-transfected cells had a lower clone formation rate, the cell cycle arrested more obviously in G2/M phase, and the apoptosis rate was higher (P<0.01), with higher levels of Bax/C-PARP (P<0.05 or P<0.01), but lower levels of Bcl-2 (P<0.01) and p-STAT3-Tyr705 (P<0.01), compare with the EV-transfected cells. Conclusions CKMT1 may inhibit the activation of STAT3, increasing the sensitivity of CNE-1 to chemotherapeutic drug DDP.