Figure 5

SB-3CT protects pericytes from ischemia-induced contraction and cell loss after embolic MCA occlusion in mice. a Colocalization of α-SMA-positive immunoreactivity with pericyte markers NG2 or desmin in the unlesioned cortex. NG2 or desmin monoclonal antibody (mAb) was used to detect pericytes with anti-mouse IgG-Alexa488 (green), followed by immunostaining with α-SMA mAb which was visualized by anti-mouse IgG-Alexa594 (red). Scale bar, 8 μm. b Representative images of ischemic cortex penumbras as compared to the corresponding contralateral regions in mice treated with SB-3CT or vehicle-treated control. Vascular cells showing colocalized (yellow) staining are laminin-positive pericytes. Top row: Pericytes identified by α-SMA appear as annular cells surrounding the lumen in the non-ischemic cortex. Middle row: Constricted vascular lumens were surrounded by contracted α-SMA immunostaining. The number of laminin-positive pericytes in the ischemic region was significantly decreased compared to the non-ischemic cortex. Bottom row: Contraction of pericytes and loss of laminin-positive pericytes were protected by SB-3CT treatment. Scale bars: 50 μm. c Quantification of the percentage of laminin-positive pericytes in cortex after treatment with SB-3CT or vehicle. Data were analyzed by one-tailed Student’s t-test: *, p < 0.05 compared ischemic hemisphere to contralateral hemisphere (paired t-test); #, p < 0.05 compared the difference between contralateral and ischemic hemisphere after SB-3CT treatment to that of the vehicle-treated control (unpaired t-test). d Quantification of the mean diameters of pericyte-encircled lumens. The average lumen diameter was calculated in approximately 300 pericytes from 4–5 randomized cortical areas of the ischemia penumbral region and the corresponding contralateral hemisphere in each brain (n = 3 in each group). Pericyte-encircled lumen diameters in the ischemic cortex were compared to those in the contralateral side treated with SB-3CT or vehicle. *, p < 0.001 compared to the non-ischemic cortex; #, p < 0.05 compared the difference between contralateral and ischemic hemisphere after SB-3CT treatment to that of the vehicle-treated control; data in panels C and D are expressed as means ± SEM.