Implications for understanding ischemic stroke as a sexually dimorphic disease: The role of pial collateral circulations

We investigated structural and functional differences in primary and pial collateral circulations in adult normotensive male and female Wistar rats. Male (n=10) and female (n=7) rats were subjected to middle cerebral artery (MCA) occlusion and changes in relative cerebral blood flow (rCBF) in MCA and pial collateral territories were measured by multi-site laser Doppler flowmetry. Rats were then transcardially perfused with a mixture of carbon black and latex, perfusion fixed and imaged to compare primary and pial collateral structure between males (n=4) and females (n=3), including lumen diameters and number. To study pial collateral function, leptomeningeal anastomoses (LMAs) were isolated and pressurized from male (n=7) and female (n=6) rats. Myogenic tone and reactivity to pressure, vascular function to pharmacological activator or inhibitor of ion channels were measured and compared. There was no difference between rCBF in both MCA and pial collateral territories during occlusion and reperfusion betwe...