Effects of D-002 on Formaldehyde-Induced Osteoarthritis in Rats

BACKGROUND: The treatment of Osteoarthritis (OA) is addressed to pain alleviation and functional status improvement. Non-steroidal anti-inflammatory drug (NSAIDs), widely prescribed for OA, have been show to produce gastrointestinal (non selective) and cardiovascular (ciclooxygenase– 2 inhibitors) adverse effects. Then, the search for new substances is justified. D-002 is a mixture of higher aliphatic beeswax alcohols with anti-inflammatory and gastroprotective, rather than gastrotoxic effects. OBJECTIVE: To investigate the effects of D-002 on formaldehyde-induced OA in rats. METHODS: OA was induced by formaldehyde injection. Animals were orally dosed with either D-002 (50, 200 and 400 mg/kg) or naproxen (NAP) (3 mg/kg), as reference drug. Controls comprised negative and vehicletreated rats. Treatments were administered for 10 days. The effects were assessed by measuring the changes on the diameters of rat ankle and paw. RESULTS: The formaldehyde injection significantly increased the diameters of rat paw and ankle as compared to the negative control group, changes that were significantly decreased by naproxen. All doses of D-002 significantly reduced these increases as compared to the positive control, but not dose-dependently. The effects of the lowest and highest doses were practically the same. The effect of the highest dose of D-002 was significantly lower than that of NAP. CONCLUSIONS: Oral administration of D-002 (50 – 400 mg/kg) significantly decreased the formaldehydeinduced increases of rat paw and ankle enlargement, albeit less effectively than NAP. These results encourage to investigate its effects on other experimental models of OA.