Methyl jasmonate a stress phytohormone attenuates LPS induced in vivo and in vitro arthritis.

The objective of present study was to screen the effect of methyl jasmonate (MJ) in lipopolysaccharide (LPS) induced in vivo and in vitro arthritis. Arthritis was induced in wistar rats by intraplantar administration of LPS (1 mg/Kg) and effect of MJ was screened in two doses (20, 40 mg/Kg, IP), indomethacin (30 mg/Kg p.o) was used as standard. The anti-nociceptive effect was evaluated through behavioral assessment viz. cold allodynia, Paw thermal hyperalgesia and Tail cold hyperalgesia on 1st, 7th, 14th, 21st and 28th day. The Myeloperoxidase (MPO), Cathepsin D (CAT-D), articular elastase (ELA), and nitrite levels were estimated in articular cartilage tissues on the 28th day. Rat paw was subjected to histopathology after radiological examination on 28th day. In vitro effect of MJ was evaluated for three concentrations (5, 10, 20 µg/ml) in LPS (1 µg/ml) stimulated CHNO001 cells. Estimation of pro-inflammatory mediators was carried using ELISA. Significant reduction in pro-inflammatory mediators was observed in MJ treated chondrocyte cells. % proteinase inhibition was assessed for 10, 50, 100, 250, 500 µg/mL and IC₅₀ was found 266.15. MJ significantly reducesnociceptive response against hot and cold allodynia. Significant reduction in MPO, ELA, and nitrite levels was observed. The CAT-D levels significantly restored. Minimum focal mild infiltration of lymphocytes was observed at synovial area in standard and MJ treated rats. These current studies conclude that MJ has protective role in arthritis.