Assessment of efficacy of simvastatin on ischemic injury of brain in an embolic model of stroke

Statins have been used in neuroprotection after cerebral ischemia. However, their mechanisms of action remain unknown. We have previously shown the protective effect of statins after cerebral ischemic injury. We have also shown that hyperthermia can exacerbate cerebral ischemic injury and that the efficacy of tissue plasminogen activator [tPA] is reduced in the presence of hyperthermia. In this study the effect of simvastatin alone or in combination with hyperthermia on brain ischemic injury was evaluated. This was an experimental study. Sample size comprised 13 groups of male rats. In four studies, the rectal and brain temperature of the rats were measured and neuroprotective effect of simvastatin alone or in combination with hyperthermia in thromboebolic stroke was evaluated. The collected data were analyzed by means of sigmastat 3.1 soft ware and statistical tests of ANOVA, Tukey and Krascal walis. The results of this study showed that brain temperature was approximately 0.5°C lower than that of rectum. Results indicate that simvastatin alone reduced the infarct volume by 46% compared to the control group [p<0.01]. Simvastatin improved neurological deficits and reduced brain edema significantly, [p<0.05]. Administration of simvastatin significantly decreased perfusion deficits and BBB permeability. These studies suggest that simvastatin is protective in an embolic model of stroke and can decrease BBB permeability and perfusion deficits in brain injured rats. MCA: middle cerebral artery, BBB: blood- brain barrier, tPA: tissue plasminogen activator

Effect of Zinc on brain GABAergic system activity in animal model of seizure induced in rat

In epileptic patients, seizure and behavioral disorders are the most important signs; therefore evaluation of these disorders using annual model can be conducive to advantage. Determination of the role of zinc in seizure and the relation of zinc concentrations in serum and hippocampus may be beneficial in developing preventive and therapeutic measures for epilepsy. The main purpose of this study was to evaluate the effect of zinc on seizure and its relation with GABAergic system activity. This was a prospective, empirical and blind study. 48 adult male Sprauge-Dawley rats were randomly assigned in six groups [n=8]. 3 groups were treated with zinc and other 3 groups with tap water. Epileptic model was induced by injection of Lithium chloride [127mg/kg] and 24 hr later, pilocarpin [50 mg/kg] into peritoneum. After first injection, group 1 and 4 received saline, group 2 and 5 bicuculine [1 mg/kg] and group 3 and 6 pentobarbital [10mg/kg] injections, Episodes of seizure disorders were recorded at 1 and 2 hrs after injection. The results of this study showed that Zn had a potentiating effect on seizure. GABA A antagonists had the same effect as Zn on seizure but GABA A agonists ameliorate it significantly. Serum zinc level didn't change significantly among the animals but hippocampus zinc declined significantly in Zn treated animals compared with those of the controls. This study shows that Zn deleterious effects on seizure were probably carried out via GABAergic system