Wound healing activity of NOE-aspirin: A pre-clinical study

Aspirin, one of the oldest non-steroidal anti-inflammatory drugs, impedes tissue repair by virtue of retarding inflammation. The present study was undertaken to find out if linking of nitrooxyethyl ester to aspirin reverses its healing-depressant propensity. Nitrooxyethyl ester of aspirin (NOE-Asp) was synthesized in our laboratory through well-established synthetic pathway, starting from aspirin through esterification with ethylene glycol and nitration with a mixture of nitric and sulfuric acids at 0 °C. The effect of NOE-Asp on phases of healing such as collagenation, wound contraction and epithelialization and on scar size of healed wound was evaluated in three wound models—incision, dead space, and excision wounds. To assess its influence on the oxidative stress, the levels of glutathione (GSH) and thiobarbiturate reactive species (TBARS) were also determined in 10-day-old granulation tissue. NOE-Asp was further screened for its anti-inflammatory activity in rat paw edema model. NOE-Asp promoted collagenation (increase in breaking strength, granulation weight, and collagen content), wound contraction, and epithelialization phases of healing. NOE-Asp also showed a significant antioxidant effect in 10-day-old granulation tissue as compared to aspirin. The results vindicate our assumption that the esterification of aspirin with nirooxyethyl group reverses the healing-suppressant effect of aspirin. The compound also showed equipotent anti-inflammatory activity as aspirin.