Linalyl acetate as a potential preventive agent against muscle wasting in rheumatoid arthritis rats chronically exposed to nicotine

Cigarette smoking has detrimental effects on rheumatoid arthritis (RA), characterized by muscle wasting. Linalyl acetate (LA), the main component of Lavandula angustifolia Mill (lavender) oil, has anti-inflammatory properties. We investigated the detrimental effects of chronic nicotine exposure in rats with RA, as well as the abilities of lavender oil and LA to prevent muscle wasting. Rats with RA induced by type II collagen were exposed to nicotine for 22 days from day 1. Lavender oil or LA was administered twice a week during the experiment. Compared with control, collagen-induced arthritis (CIA) and chronic nicotine exposure plus CIA (NicoCIA) showed increases in hind paw thickness and serum interleukin (IL)-6 and decreases in body weight and serum insulin-like growth factor (IGF)-1 levels. Moreover, weight and fiber cross-sectional area of the gastrocnemius muscle were much lower, and mitochondrial membrane potential of the gastrocnemius muscle was higher, in the NicoCIA than in the CIA. These alterations in the NicoCIA were prevented by lavender oil and LA. Importantly, LA showed greater activity than lavender oil in preventing IGF-1 reduction in the NicoCIA. These findings suggest that lavender oil and LA may have preventive benefit in RA by counteracting muscle wasting associated with chronic nicotine exposure.