南方医科大学学报

南方医科大学学报 ›› 2019, Vol. 39 ›› Issue (05): 579-.doi: 10.12122/j.issn.1673-4254.2019.05.13

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碘乙酸钠诱导的骨关节炎疼痛大鼠背根神经节KCNA2 的表达

赵其宏，王其友，徐杰，王嘉锋，邓小明   

  • 出版日期:2019-05-20 发布日期:2019-05-20

Expression of KCNA2 in the dorsal root ganglia of rats with osteoarthritis pain induced by monoiodoacetate

  • Online:2019-05-20 Published:2019-05-20

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摘要： 目的研究背根神经节（DRG）神经元电压门控钾离子通道亚基KCNA2在碘乙酸钠诱导的骨关节炎（OA）疼痛模型大鼠 中的表达及机制。方法156只成年雄性SD大鼠随机均分为空白对照组（C组）、生理盐水组（S组）和骨关节炎组（OA组），通过 膝关节腔内注射碘乙酸钠建立骨关节炎模型。分别于注射前、注射后1、2、4、6周测定大鼠机械刺激缩足阈值（PWMT）。注射后 4周，HE及番红固绿染色观察膝关节病理学变化，免疫荧光染色检测DRG神经元活化转录因子-3（ATF-3）、诱生型一氧化氮合 酶（iNOS）的表达情况。RT-qPCR检测1、2、4、6周DRG神经元Kcna2 mRNA表达，4周时Western blot分析KCNA2的表达情况、 MSPCR检测Kcna2甲基化程度。结果与注射前相比，OA组2、4、6周PWMT显著降低（P<0.05或P<0.001）；与C组相比，OA 组2、4、6周PWMT显著降低（P<0.05或P<0.001）。OA组大鼠膝关节软骨表面断裂、缺损，骨质增生，潮线模糊不清；C、S组未发 现明显异常。4周时OA组ATF-3与iNOS表达显著增高（P<0.01），2、4、6周Kcna2 mRNA及4周KCNA2表达显著降低（P<0.05 或P<0.01）、Kcna2 甲基化程度显著增高（P<0.01）。结论骨关节炎疼痛大鼠DRG神经元KCNA2 的表达降低，其机制可能与 Kcna2启动子区域甲基化增强有关。

Abstract: Objective To investigate the changes in the expression of voltage-gated potassium channel subunit KCNA2 in the dorsal root ganglion (DRG) neurons of rats with osteoarthritis (OA) pain induced by sodium monoiodoacetate and explore the mechanism. Methods A total of 156 adult male Sprague-Dawley rats were randomly divided into blank control group, saline group and intra-articular monoiodoacetate injection-induced OAgroup. The paw withdrawal mechanical threshold (PWMT) was measured before and at 1, 2, 4, and 6 weeks after monoiodoacetate injection. At 4 weeks after the injection, the pathological changes in the knee joints were analyzed using HE staining and Safranin O-Fast Green staining, and the expression of activating transcription factor 3 (ATF-3) and inducible nitric oxide synthase (iNOS) in the DRG neurons were detected by immunofluorescence staining. The expression of Kcna2 mRNA in the DRG neurons was detected by RT-qPCR at 1, 2, 4 and 6 weeks after the injection. The expression of KCNA2 in the DRG was measured by Western blotting, and the methylation level of Kcna2 promoter region was measured by MSPCR at 4 weeks after the injection. Results The PWMT of the rats in OA group was significantly decreased at 2, 4, and 6 weeks after the injection as compared with the baseline (P<0.05 or P<0.001) as well as the control group (P<0.05 or P<0.001). Four weeks after the intra-articular injection, fractures and defects on the surface of the articular cartilage, bone hyperplasia, and blurred tidal line were observed in the rats in OA group, but no obvious pathological changes were detected in the control or saline groups. Compared with those in the control group, the expressions of ATF-3 and iNOS were significantly increased (P<0.01) at 4 weeks after injection; the expression of Kcna2 mRNA at 2, 4 and 6 weeks and the expression of KCNA2 protein at 4 weeks were all significantly decreased (P<0.05 or P<0.01), and the methylation level of Kcna2 gene was significantly increased at 4 weeks after the injection in OA group (P<0.01). Conclusion The expression of KCNA2 is decreased in the DRG neurons of rats with OApain likely as a result of enhanced methylation of Kcna2 promoter region.