Effect of Intraperitoneally Injection of Different Doses of Lovastatin on Pain and Inflammatory Response Induced by Formalin in Mice

Problem statement: The 3-Hydroxy-3-Methyl Glutaryl-CoA (HMG-CoA) reductase inhibitors (statins) have been unequivocally shown to reduce cardiovascular morbidity and mortality. Their lipid-lowering actions are by reversible and competitive inhibition of the enzyme HMG-CoA reductase, a precursor of cholesterol. It has been suggested that statins appear to have therapeutic benefits in diseases that are unrelated to elevated serum cholesterol levels, such as pain and inflammatory. The aim of this study was to determination the effect of intraperitoneally injection of different doses of lovastatin on pain and inflammatory response induced by formalin in mice. Approach: Mice were divided into 9 groups randomly: the first group received saline normal (ip) (saline group); the second group received Carboxymethylcellulose (CMC) 0.5% (ip) (vehicle group) and the next groups received respectively different doses of lovastatin (1, 5, 10, 20, 40, 80 and 100 mg kg daily^-1) for 4 days (ip) before formalin test. After intrapawly injection of formalin, the time of hind paw biting and licking time measured in 5 min interval for an hour. Results: Results showed that formalin induces biphasic pain response (the first phase: 0-5 min and the second phase 15-40 min after injection). Intraperitoneal injection of lovastatin showed significant (p<0.05) decrease of pain responses in the first and the second phase in a dose dependently manner. Conclusion: According to our results, lovastatin has analgesic and anti-inflammatory effects on mice. Nevertheless, new studies must be carried out in order to determine the beneficial effects of statins in treatment of pain and inflammatory.