Effect of hypertension and peroxynitrite decomposition with FeTMPyP on CBF and stroke outcome

We investigated the effect of peroxynitrite decomposition catalyst FeTMPyP treatment on perfusion deficit, vascular function and stroke outcome in Wistar (n=26) and spontaneously hypertensive rats stroke-prone (SHRSP; n=26) that underwent tMCAO for 2h or Sham operation. Peri-infarct CBF was measured by hydrogen clearance in the absence or presence of FeTMPyP (10mg/kg, i.v.) or vehicle 10min before reperfusion. Myogenic tone of parenchymal arterioles (PAs) was measured as an indication of small vessel resistance (SVR). Baseline CBF was similar between Wistar and SHRSP (114 +/- 12 vs. 132 +/- 9mL/100g/min); however, MCAO caused greater perfusion deficit in SHRSP (24 +/- 6 vs. 7 +/- 1mL/100g/min; p<0.05) and increased infarct volume by TTC (12 +/- 6 vs. 32 +/- 2%; p<0.05). Reperfusion CBF was decreased from baseline in both SHRSP and Wistar (54 +/- 16 and 46 +/- 19mL/100g/min; p<0.05), suggesting increased infarction in SHRSP was related to greater perfusion deficit. PAs from SHRSP had increased tone vs. Wistar that was enhanced after tMCAO. FeTMPyP treatment did not affect CBF during ischemia or reperfusion, or tone of PAs, but decreased the incidence of hemorrhage in SHRSP by 50%. Thus, increased tone in PAs from SHRSP could increase perfusion deficit during MCAO that was not alleviated by FeTMPyP.