Effect of raloxifene on cerebral vasospasm following experimental subarachnoid hemorrhage in rats

Comparing Protection of Remote Limb with Resveratrol Preconditioning following Rodent Subarachnoid Hemorrhage

Background: Preventing delayed cerebral ischemia (DCI) after subarachnoid hemorrhage (SAH) remains an important therapeutic target. Preconditioning stimulates multiple endogenous protective mechanisms and may be a suitable treatment for DCI following SAH. We here compare remote limb conditioning with resveratrol conditioning in a clinically relevant SAH model. Methods: We produced a SAH in 39 male Sprague Dawley rats using a single injection model. Animals were randomized to four groups: repetitive limb conditioning with a blood pressure cuff, sham conditioning, intraperitoneal resveratrol (10 mg/kg) or intraperitoneal vehicle administered at 24, 48 and 72 h after SAH. On day 4 neurological and behavioral scores were obtained, and animals were euthanized. The cross-sectional area of the basilar artery was measured at the vertebrobasilar junction, and at the mid and distal segments. Hippocampal cells were counted in both hemispheres and normalized per mm length. We compared true limb preconditioning with sham conditioning and resveratrol with vehicle preconditioning. Results: The cross-sectional area of the mid-basilar artery in the true limb preconditioning group was significantly larger by 43% (p = 0.03) when compared with the sham preconditioning group. No differences in the cross-sectional area were found in the resveratrol-treated group when compared to the vehicle-treated group. We found no differences in the neuro score, behavioral score, and in mean hippocampal neuron counts between the groups. Conclusion: We found beneficial vascular effects of remote limb preconditioning on SAH-induced basilar artery vasoconstriction. Our findings support further studies of limb preconditioning as a potential treatment after SAH.

Effects of intramuscular parecoxib administration on vasospasm in an experimental subarachnoid hemorrhage model

AIM

We examined whether intramuscular parecoxib administration has a preventive or therapeutic effect on vasospasm following experimental subarachnoid hemorrhage (SAH).

MATERIALS AND METHODS

Twenty New Zealand White Rabbits were assigned randomly to one of four groups. Animals in Group I were not subjected to SAH (control group). Animals in all other groups were subjected to SAH. Animals in Group II received no treatment after SAH induction (SAH group). Animals in Group III received intramuscular parecoxib (diluted with saline) injection at 6 and at 30 hours after SAH (treatment group). Animals in Group IV received only intramuscular saline injection at 6 and at 30 hours after SAH (vehicle group). Animals were euthanized by perfusion and fixation 48 hours after SAH induction. Basilar artery cross-sectional areas and wall thicknesses were measured. Statistical comparisons were performed using Kruskal-Wallis and Mann-Whitney U tests.

RESULTS

Basilar artery cross-sectional areas in the treatment group were significantly higher than in the SAH or vehicle group (p<.05). Basilar artery wall thickness in the treatment group was significantly smaller than in the SAH or vehicle group (p<.05).

CONCLUSION

Our study revealed that intramuscular administration of parecoxib significantly attenuates vasospasm following experimental SAH.

Comparison of intrathecal cilostazol and nimodipine treatments in subarachnoid hemorrhage: an experimental study in rabbits

OBJECTIVE

intrathecal administration of calcium channel antagonists has been proposed to reduce cerebral vasospasm (CVS) in animal subarachnoid hemorrhage (SAH) models. Also, delayed CVS treatment model with oral administration of cilostazol can be seen in the literature.

METHODS

in this study, 25 male New Zealand white rabbits were randomly assigned to five groups: control, SAH only, SAH/nimodipine, SAH/cilostazol, SAH/vehicle. The animals' basilar arteries were sectioned from four separate zones and four sections were obtained from each rabbit. Basilar artery luminal section areas were measured by using SPOT for windows Version 4.1 computer program.

RESULTS

basilar artery luminal section areas in SAH/ nimodipine and SAH/ cilostazol groups were significantly higher than SAH only group (P < 0.05).

CONCLUSION

phosphodiesterase 3 inhibitor cilostazol has vasodilatory effects without affecting cerebral blood flow. Nimodipine is a calcium channel blocker and is still used in vasospasm therapy either oral or intravenously. This study demonstrates that prophylactic bolus intrathecal administration of either cilostazol or nimodipine equally prevents SAH-associated CVS in an animal model. We therefore propose that cilostazol is a candidate for clinical trials in the treatment of delayed vasospasm.