English

Abstract

Previous studies demonstrated therapeutic effects for calcium channel blockers (CCBs) in control of acute inflammation. There are little reports on the effect of these blockers on chronic inflammation. In this study, we investigated the effects of CCBs on chronic inflammation using complete Ferund's adjuvant (CFA) induced inflammation in the rat knee joints. This experimental study was carried out on 80 male Wistar rats. Calcium channel blockers (verapamil and nifedipine) were used in doses of 100 and 800 µg/kg. For induction of chronic inflammation, CFA (0.2 ml) was injected into the right knee joint. The changes in blood flow, and local temperature of the animal's knee joint were measured by laser Doppler flowmetry and also the knee diameter was measured by a caliper, on 0, 7, 14, 21, and 28 days after CFA injection. CFA injection significantly increased blood flow from day 1 to 28 as compared to the day 0. Administration of both verapamil and nifedipine (100 and 800 µg/kg) significantly decreased the effect of CFA on increasing blood flow (all p < 0.05). Administration of both verapamil and nifedipine (100 and 800 µg/kg) significantly inhibited the effect of CFA on increasing knee temperature (all p < 0.05). Injection of CFA increased the knee joint diameter for all 28 days after injection. Both low and high doses of nifedipine and verapamil could inhibit the increased diameter that is induced by CFA injection (all p < 0.05). The effects of CCBs on measured parameter were comparable with the effect of ibuprofen (which is a standard anti-inflammatory drug) on these parameters. The results revealed that CCBs inhibited the increased rat knee blood flow, diameter and temperature in chronic inflammation induced by CFA. Therefore, the underlying mechanisms for reduction of chronic inflammation possibly are modulated by these blockers. Key words: Chronic inflammation, verapamil, nifedipine, complete Ferund's adjuvant (CFA).