The expression of P- and E-selectins in three models of middle cerebral artery occlusion

Abstract

The expression and localization of P- and E-selectins in rat brain ( n=126) were examined using immunohistochemical techniques at various time points after induction of middle cerebral artery (MCA) occlusion in the suture, thrombotic and embolic models of stroke. Expression of P- or E-selectin was not observed in brain tissue of sham operated control rats ( n=9). P-selectin immunoreactivity was detected as early as 15 min and decreased to control level at 1 h after the onset of the MCA occlusion in all three models. P-selectin then slightly increased at 2 h and peaked at 6 h after MCA occlusion. E-selectin immunoreactivity was first observed at 2 h and peaked at 6 h and 12 h of after MCA occlusion in all three models. P- and E-selectin immunoreactivity was colocalized with von Willebrand factor immunoreactive microvessels. 90.4±2.0% of all vessels expressing P-selectin immunoreactivity were 7.5 to 30.0 μm in diameter; 3.6±1.4% were contained in vessels smaller than 7.5 μm, and 6.0±1.8% were localized in vessels greater than 30.0 μm in diameter. The percent distribution of E-selectin immunoreactive vessels were 75.9±2.1% in vessels 7.5 to 30.0 μm in diameter; 23.6±2.2% were in vessels smaller than 7.5 μm, and 0.6±0.4% were localized in vessels greater than 30.0 μm in diameter. These findings indicate that the temporal profiles of P- and E-selectin expression are independent of these models of MCA occlusion and are consistent with the time course of selectin mediated leukocyte infiltration after focal cerebral ischemia in the rat.