Résumé
Effect of water deprivation for 24 h on blood parameters and platelet aggregation in pial arterioles of lead-treated mice was investigated. Exposure to lead was made by intraperitoneal injections for 24 h of lead acetate dissolved in a 5% glucose solution vehicle. Three doses of lead were used, a low dose of 0.1 mg/kg, intermediate dose of 0.5 mg/kg and a high dose of 1.0 mg/kg. Adult male mice were divided into four groups of 10 each. Platelet aggregation in pial microvessels was induced photochemically, in vivo, in anaesthetized [urethane, 1 - 2 mg/g, i.p] animals by activation of circulating sodium fluorescein [0.1 mL of 5% solution /25g, i.v.] with an intense mercury light. The time required for the first platelet aggregate to appear in pial arterioles was significantly [P < 0.05] shorter [166 +/- 27, 154 +/- 58, 218 +/- 68 sec; in low, intermediate and high doses of lead, respectively] than in control [276 +/- 63 sec]. Dehydration significantly reduced both the time requied for the first platelet aggregate [61 +/- 21 vs 125 +/- 31 sec] and the time to full occlusion [134 +/- 18 vs 239 +/- 68 sec, lead-treated vs control, P < 0.05].Blood data of dehydrated mice confirmed haemoconcentration and lead treatment did not have any influence, except haemoglobin and haematocrit in the high dose group which showed significant differences from those of control [P < 0.05]. These data revealed that lead can cause cerebrovascular thrombosis after 24 h of exposure and its effect can be enhanced under water deprivation conditions