Detrimental effects of transient cerebral ischemia on middle cerebral artery mitochondria in female rats

Am J Physiol Heart Circ Physiol. 2022 Nov 11. doi: 10.1152/ajpheart.00346.2022. Online ahead of print.ABSTRACTMitochondrial numbers and dynamics in brain blood vessels differ between young male and female rats under physiological conditions, but how these differences are affected by stroke is unclear. In males, we found that mitochondrial numbers, possibly due to mitochondrial fission, in large middle cerebral arteries (MCAs) increased following transient middle cerebral artery occlusion (tMCAO). However, mitochondrial effects of stroke on MCAs of female rats have not been studied. To address this disparity, we conducted morphological, biochemical, and functional studies using electron microscopy, western blot, mitochondrial respiration, and Ca2+ sparks activity measurements in MCAs of female, naïve or sham Sprague-Dawley rats before and 48 h after 90 min of tMCAO. Adverse changes in mitochondrial characteristics and the relationship between mitochondria and sarcoplasmic reticulum (SR) in MCAs were present on both sides. However, mitochondria and mitochondrial/SR associations were often within the range of normal appearance. Mitochondrial protein levels were similar between ipsilateral (ipsi) and contralateral (contra) sides. Non-respiratory oxygen consumption, maximal respiration, and spare respiratory capacity were similar between ipsi and contra but were reduced compared with sham. Basal respiration, proton leak, and ATP production were similar among MCAs. Ca2+ activity i...
Source: American Journal of Physiology. Heart and Circulatory Physiology - Category: Physiology Authors: Source Type: research