SGK-1通过软骨破坏和炎性疼痛传导参与颞下颌关节骨关节炎

The involvement of SGK-1 in cartilage destruction and inflammatory pain in temporomandibular joint osteoarthritis

目的探究血清和糖皮质激素诱导的蛋白激酶1(SGK-1)在大鼠颞下颌关节(TMJ)骨关节炎(TMJ-OA)中的作用。方法16只大鼠随机分为对照(Control)组和TMJ-OA组,TMJ-OA组关节腔内注射碘乙酸钠(MIA),Control组注射等量0.9%氯化钠溶液;von-Frey测量头部退缩阈值(HWT)评估疼痛行为;苏木精伊红(HE)、番红固绿染色观察TMJ组织学结构变化;qRT-PCR检测大鼠髁突软骨(MCC)中SGK-1、基质金属蛋白酶13(MMP-13)、白介素(IL)-1β、环氧合酶(COX-2)mRNA表达。HE染色观察三叉神经节(TG)组织病理变化以及检测TG中SGK-1、COX-2 mRNA的表达。结果MIA关节腔内注射28 d可引起大鼠头退缩阈值(HWT)降低,MCC及软骨下骨结构紊乱,TG神经纤维空泡样变。qRT-PCR检查显示,与Control组相比,TMJ-OA组大鼠MCC和TG组织中SGK-1表达升高(P<0.05)。结论SGK-1可能通过关节局部软骨破坏和炎性疼痛传导两种途径参与TMJ-OA的病理过程。

Objective This study aimed to explore the role of SGK-1 in the occurrence of temporomandibular joint(TMJ) osteoarthritis(TMJ-OA). Methods Sixteen rats were randomly divided into Control group(Control group) and TMJ-OA group(TMJ-OA group), and TMJ-OA group was injected with sodium iodoacetate(MIA) intra articular cavity while Control group was injected with 0.9% sodium chloride solution. Pain behavior was assessed by measuring the head withdrawal threshold(HWT) with a von-Frey apparatus. Hematoxylin-eosin(HE) and Safranin O-fast green stains were used to observe the histological structure changes of the condyle of TMJ-OA rats. Real-time PCR was performed to exam the expression levels of mRNA of SGK-1, MMP-13, IL-1β, COX-2 in mandibular condylar cartilage(MCC). HE stain was used to observe the histological structure changes of the trigeminal ganglion(TG) of TMJ-OA rats. Real-time PCR was performed to exam the expression levels of mRNA of SGK-1, COX-2 in TG. Results MIA injection induced typical OA-like lesions in the TMJ within 28 days. Administration of MIA led to the significant decrease in HWT, disordered of the condyle cartilage and subchondral bone structure, demyelination aggravated of nerve fibers in TMJ rats. Compared with rats in Control groups, the expression levels of SGK-1 in MCC and TG of rats in TMJ-OA group were upregulated. Conclusion In the pathological process of TMJ-OA, SGK-1 may plays an important role not only in cartilage structural damage but also in pain transmission.