Recovery of the Functional Activity of K<sub>ATP</sub>-Channels of Pial Arteries after Ischemia/Reperfusion Using Cell Therapy

Abstract

This study aims to examine the efficiency of intravenous transplantation of human mesenchymal stem cells (hMSCs) performed 7 days after cerebral ischemia/reperfusion (I/R) for recovery of the functional activity of KATP-channels of cerebral arteries. Using a device for intravital visualization of pial vessels, the reaction of arteries to the KATP-channel blocker glibenclamide (GB), the activator of the same channels of pinacidil (PI), acetylcholine (ACh), and ACh against a background of GB action (ACh/GB) 14 and 21 days after I/R and intravenous hMSC transplantation performed 7 days after ischemic exposure. On exposure to GB 14 days after I/R, 1.5–1.8 times fewer arteries narrowed than in the sham–operated (SO) rats. By day 21 after I/R, the constriction reaction was completely restored, except for arteries with a diameter more 40 μm. In the cell–therapy group, the constrictor response to GB was completely recovered to the level of SO animals in arteries with a diameter less than 40 μm by 14 day after I/R exposure; in arteries with a diameter of more than 40 μm, the constriction reaction did not recover until 21 days. The number of dilations per ACh/GB compared to a clear ACh in SO rats was reduced in 1.6–1.8 times on 14 day after I/R and in 1.6–6.6 after 21 days. In I/R animals on 14 day, the number of dilatations per ACh/GB compared to clear ACh was significantly increased in arteries with a diameter of more than 20 μm by 1.5–1.7 times, and after 21 days in arteries with a diameter of more than 40 μm by 1.2 times. After the introduction of hMSC, GB blocked ACh–mediated dilation in arteries less than 40 μm in diameter both on days 14 and 21 after I/R. In arteries with a diameter of more than 40 μm the functional activity of KATP-channels did not recover until 21 days. Conclusion. I/R of the rat cerebral cortex reduces the contribution of KATP-channels to maintaining the basal tone of the pial arteries and almost completely excludes these channels from the formation of ACh–mediated dilation during 21 days of the postischemic period. Practically did not participate in the dilatory response. Intravenous transplantation of hMSC, performed 7 days after I/R, results in restoration of participation of SMC KATP-channels in maintaining the basal tone and ACh–mediated dilatation of pial arteries with a diameter less than 40 μm already 14 days after I/R.