Enoxaparin, a low molecular weight heparin decreases infarct size and improves sensorimotor function in a rat model of focal cerebral ischemia

Possible neuroprotective effects of the low molecular weight heparin (LMWH) enoxaparin sodium (Lovenox) were evaluated in a rat model of focal ischemi a. Male Sprague-Dawley rats were subjected to 90 min of occlusion of the ri ght middle cerebral artery using the intraluminal suture method. Enoxaparin at doses of 0, 10 or 15 mg/kg was administered to groups of rats 1,8, 24 a nd 32 h after artery occlusion. Motor impairment was evaluated by performan ce on the traverse beam and accelerating rotarod tests. Animals were sacrif iced 48 h after occlusion and brain sections were stained with 2% 2,3,5-tri phenyltetrazolium chloride for determination of infarct volume. Forty perce nt of the rats receiving 15 mg/kg enoxaparin died as a result of intracrani al hemorrhage. Untreated rats exhibited large lesions involving the caudate putamen and much of the cortex. In enoxaparin - treated rats the damage wa s mainly confined to the caudate putamen. The sensorimotor behavior of the 10 mg/kg enoxaparin group was significantly better than that of untreated a nimals. Motor performance of the survivors in the 15 mg/kg group was poor d ue to hypoactivity and weakness resulting from excessive bleeding. These re sults suggest that LMWH may have a neuroprotective function. (C) 2000 Elsev ier Science Ireland Ltd. All rights reserved.