放射后炎症反应对大鼠颌下腺紧密连接蛋白的影响

Effect of Post-irradiation Inflammatory Response on Tight Junction Proteins in Rat Submandibular Glands

目的:观察颌下腺放射后炎症反应导致的紧密连接(TJ)蛋白改变及对旁细胞途径的影响。方法:24只大鼠随机分为对照组及放射1、6、12周组。对照组未照射,放射组右侧颌下腺接受20 Gy照射,特定时间点检测5 min唾液分泌量。苏木精-伊红(HE)染色观察颌下腺组织形态;免疫组织化学(IHC)染色观察肿瘤坏死因子(TNF)-α阳性表达;Western blot及免疫荧光(IF)染色观察claudin-1、claudin-3及水通道蛋白5(AQP5)水平及分布,实时定量聚合酶链反应(RT-qPCR)检测mRNA表达;酶联免疫吸附剂测定(ELISA)检测TNF-α、白细胞介素(IL)-1β及IL-6水平。结果:放射后唾液分泌量降低;组织间质水肿增宽、脱颗粒改变、空泡化及炎症细胞浸润持续加重;炎症因子水平增加;claudin-1、claudin-3和AQP5蛋白水平及mRNA表达量异常,荧光染色强度减弱。结论:放射后炎症反应可能是颌下腺紧密连接蛋白异常,旁细胞途径破坏的重要影响因素。

Objective:To observe the changes of tight junction(TJ)proteins induced by post-irradiation inflammation and its effect on paracellular pathway in submandibular glands(SMGs).Methods:Twenty-four rats were randomly divided into Control group and 1,6,and 12 weeks post-irradiation group.The control group was not irradiated.In radiation group,a dose of 20 Gy irradiation was applied on the right SMGs.At specific time points,saliva secretion was measured within 5 min.The pathological changes were observed by HE staining.Immunohistochemical staining was used to investigate the positive expression of TNF-α.The levels and distribution of claudin-1,claudin-3,and AQP5 were detected by WB and immunofluorescence staining.The mRNA expression was detected by RT-qPCR.The levels of TNF-α,IL-1β,and IL-6 were detected by ELISA.Results:The salivary secretion was decreased after 1,6,and 12 weeks in the irradiation group.The interstitial edema,degranulation,vacuolation,and inflammatory cell infiltration of SMGs were increased continuously.The levels of inflammatory cytokines were increased.The levels and mRNA expression of claudin-1,claudin-3,and AQP5 were down-regulated,and the relative fluorescence intensity was decreased.Conclusion:The inflammatory response after radiation may play a vital role affecting the abnormities of TJ proteins in rat SMGs and the destruction of paracellular pathway.