Role of cimetidine in the prevention of intimal hyperplasia in rat carotid artery.

In vitro studies have revealed that histamine increases smooth muscle cell proliferation and migration, an effect abolished by the H2 antagonist cimetidine. This study examined the effect of cimetidine on intimal hyperplasia in vivo. Thirty male Wistar rats underwent endothelial denudation of the left carotid artery; 15 received cimetidine 350 mg per kg per day for four weeks and 15 received vehicle only. Four weeks after injury the left carotid arteries were perfusion fixed and harvested. Morphometric analysis revealed that there was no significant difference between the intima:media ratio of rats treated with cimetidine (median (interquartile range (i.q.r.)) 1.69 (0.59)) and those treated with vehicle (median (i.q.r.) 1.59 (0.59), P = 0.28). Similarly, the percentage luminal reduction was not significantly different between the groups (median (i.q.r.) 54.7 (19.9) per cent and 45.8 (13.4) per cent respectively, P = 0.30). It is concluded that treatment with cimetidine does not reduce the formation of intimal hyperplasia in rat carotid arteries de-endothelialized with a balloon catheter.