Effects of garlic and nimodipine on cerebral blood flow and their neuroprotective effects after brain ischemia in rabbit

ABSTRACT

Nimodipine has been shown to have a neuroprotective effect. Garlic also displays features that are potentially effective in inhibiting ischemic damage. In this study the efficacy of both garlic and nimodipine in preventing ischemic brain injury were assessed. Twenty-four rabbits were divided into four groups nimodipine-treated group [NP], garlic-treated group [GR], normal saline group [NS], and polyethylene glycol-treated as the vehicle group [VH]. All animals were subjected to 15 minutes of bilateral common carotid artery [CCA] occlusion. NP and GR groups received garlic and nimodipine 60 minutes before occlusion of the CCA respectively. Cerebral blood flow [CBF] was measured by Laser Doppler flowmetry, during and after the occlusion. Histopathology of the brain was blindly evaluated. The percentage of degenerated cells in the hippocampus was estimated and vascular congestion was graded on a 3-point scale [0, I, II]. After reperfusion, nimodipine and garlic increased the cerebral blood flow [CBF] by 41% and 24% respectively. Comparing these values to the extent of CBF increase in the VH and NS [2% in both] groups, the differences were statistically significant [p<0.05]. The percentage of degenerated neuronal cells in zone CA1 was 23%, 31%, 43% and 44% in NP, GR, VH and NS groups, respectively. NP and GR showed a higher grade of congestion compared to control groups [VH and NS][p<0.05]. This study demonstrates that neuronal damage to the rabbit hippocampus is reduced by garlic administration, although nimodipine can increase CBF more effectively