Effects of Acupuncture at ST36 and SP6 on Activity Levels and Pain Thresholds Through Interleukin-1, Interleukin-6, Cortisol, and Matrix Metalloproteinase-13 Modulation in an Osteoarthritis Rat Model

Objectives: Osteoarthritis (OA) is a degenerative joint disease characterized by cartilage degradation, inflammation, and altered stress-related responses.This preclinical study examined the effects of acupuncture at ST36 (stomach 36), SP6 (spleen 6), and their combination on pain thresholds, locomotor function, and inflammation and stress-related biomarkers in a monosodium iodoacetate (MIA)-induced OA rat model.Methods: Thirty male Wistar rats were randomized into five groups: a healthy control, an OA control, and three acupuncture-treated groups (ST36, SP6, and ST36 + SP6).Acupuncture-treated groups underwent eight 15-min sessions of acupuncture per day.Pain thresholds and locomotor activity were assessed before and after treatment.Joint tissue was analyzed for interleukin (IL)-1, IL-6, cortisol, and matrix metalloproteinase-13 (MMP-13) levels.Group differences were analyzed using appropriate parametric or nonparametric tests, and the associations between biomarkers and behavioral outcomes were assessed using Pearson correlation analysis.Results: The acupuncture-treated rats showed increased pain thresholds (~5.3 g to 9.93-11.60g, p < 0.05) and higher locomotor activity compared with those in the OA controls.IL-1, IL-6, cortisol, and MMP-13 levels were reduced from pretreatment levels in all acupuncture groups.Biomarker levels were negatively correlated with pain thresholds (r = -0.526 to -0.686) and locomotor activity (r = -0.537 to -0.893; all p < 0.01).Conclusion: In rats with MIA-induced OA, acupuncture was associated with improved pain thresholds and locomotor outcomes and changes in inflammation and stress-related biomarker levels, providing exploratory preclinical evidence linking biomarker modulation with functional responses.