Skiöldebrand Eva, Ley Cecilia, Björklund Ulrika, Lindahl Anders, Hansson Elisabeth
Department of Clinical Chemistry and Transfusion Medicine, Institute of Biomedicine, Sahlgrenska University Hospital, Gothenburg University, Gothenburg, Sweden.
Section of Pathology, Department of Biomedical Sciences and Veterinary Public Health, Swedish University of Agricultural Sciences, Uppsala, Sweden.
Vet Anim Sci. 2019 Sep 27;8:100078. doi: 10.1016/j.vas.2019.100078. eCollection 2019 Dec.
Osteoarthritis is a pain-associated progressive disease and pain mediators, such as opioid receptors, expressed in articular cartilage could represent novel therapeutic targets. Acute and chronic stages of OA indicate different metabolic abilities of the chondrocytes depending on inflammatory state. This study aimed to investigate the response of healthy and osteoarthritic chondrocytes and their expression and release of pain mediators in response to acute inflammation. Interleukin-1 beta (IL-1β) and lipopolysaccharide (LPS) were used to induce an acute inflammatory response in cultured equine chondrocytes harvested from healthy joints (HC) and osteoarthritic joints (OAC), the latter representing acute exacerbation of a chronic inflammatory state. Intracellular Ca release was determined after exposure to serotonin (5-hydroxytryptamine (5-HT), glutamate or ATP. Protein expression levels of F- and G-actin, representing actin rearrangement, and opioid receptors were investigated. Glutamate concentrations in culture media were measured. Cartilage was immunohistochemically stained for µ (MOR), κ (KOR), and δ (DOR) opioid receptors. Upon exposure to acute inflammatory stimuli, OAC showed increased intracellular Ca release after 5-HT stimulation and increased expression of MOR and KOR. When cells were stimulated by inflammatory mediators, glutamate release was increased in both HC and OAC. Immunostaining for MOR was strong in OA cartilage, whereas KOR was less strongly expressed. DOR was not expressed by cultured HC and OAC and immunostaining of OA cartilage equivocal. We show that chondrocytes in different inflammatory stages react differently to the neurotransmitter 5-HT with respect to intracellular Ca release and expression of peripheral pain mediators. Our findings suggest that opioids and neurotransmitters are important in the progression of equine OA. The inflammatory stage of OA (acute chronic) should be taken into consideration when therapeutic strategies are being developed.
骨关节炎是一种与疼痛相关的进行性疾病，关节软骨中表达的疼痛介质，如阿片受体，可能代表新的治疗靶点。骨关节炎的急性和慢性阶段表明，软骨细胞的代谢能力因炎症状态而异。本研究旨在调查健康和骨关节炎软骨细胞的反应，以及它们在急性炎症反应中疼痛介质的表达和释放。白细胞介素-1β（IL-1β）和脂多糖（LPS）用于在从健康关节（HC）和骨关节炎关节（OAC）采集的培养马软骨细胞中诱导急性炎症反应，后者代表慢性炎症状态的急性加重。在暴露于血清素（5-羟色胺（5-HT））、谷氨酸或三磷酸腺苷后，测定细胞内钙释放。研究了代表肌动蛋白重排的F-肌动蛋白和G-肌动蛋白以及阿片受体的蛋白质表达水平。测量培养基中的谷氨酸浓度。对软骨进行μ（MOR）、κ（KOR）和δ（DOR）阿片受体的免疫组织化学染色。暴露于急性炎症刺激后，OAC在5-HT刺激后细胞内钙释放增加，MOR和KOR表达增加。当细胞受到炎症介质刺激时，HC和OAC中的谷氨酸释放均增加。OA软骨中MOR的免疫染色很强，而KOR的表达较弱。培养的HC和OAC未表达DOR，OA软骨的免疫染色不明确。我们表明，不同炎症阶段的软骨细胞在细胞内钙释放和外周疼痛介质表达方面对神经递质5-HT的反应不同。我们的研究结果表明，阿片类药物和神经递质在马骨关节炎的进展中很重要。在制定治疗策略时，应考虑骨关节炎的炎症阶段（急性 慢性）。
