Evaluation of analgesic and prophylactic activity of curcumin against chikungunya-infected acute/chronic arthralgic mice.

Chikungunya virus (CHIKV) infection, a global public health problem, might lead to acute/chronic polyarthritis causing long-term morbidity among infected patients. But, except nonsteroidal anti-inflammatory drugs (NSAIDs) with gastrointestinal, cardiovascular, and immune-related side-effects, no Food and Drug Administration (FDA)-approved analgesic drug is available till date for the treatment of CHIKV-induced arthritis. Curcumin, a plant product with minimal toxicity has been FDA-approved as a Generally Recognized As Safe drug. This study aimed to determine the analgesic and prophylactic effect of curcumin, if any, among CHIKV-induced arthralgic mice. Arthritic pain was evaluated by von Frey assay, locomotory behavior by open-field test, and feet swelling by calipers. Cartilage integrity and proteoglycan loss were evaluated by Safranin O staining followed by Osteoarthritis Research Society International (OARSI), Standardized Microscopic Arthritis Scoring of Histological sections (SMASH) score, and type II collagen loss by immunohistochemistry. Mice were administered high (HD), mid (MD), and low (LD) curcumin doses, before (PT: pretreatment), during (CT: cotreatment) and after (Post-T: posttreatment) CHIKV-infection. Curcumin treatment using PT (2000 mg/kg), CT , and Post-T (1000 mg/kg) significantly alleviated CHIKV-induced arthritic pain by improving pain-threshold, locomotory behavior and reducing feet swelling of infected mice. Also, decreased proteoglycan loss and cartilage erosion with lower OARSI, SMASH scores were observed among these three subgroups compared to infected ones. Compared to infected ones, one- to twofold increased intensity of type II collagen in knee medial femoral condyle and medial tibial plateau regions of these subgroups was observed by immunohistochemical staining. Thus, this study highlighted both the analgesic (CT, Post-T), and prophylactic (PT) activity of curcumin in alleviating CHIKV-induced acute/chronic arthritis within mouse model.