Figure 1: Early-onset and progressive BBB disruption through both MMP-independent and -dependent mechanisms in an in vivo stroke model. | Nature Communications

Figure 1: Early-onset and progressive BBB disruption through both MMP-independent and -dependent mechanisms in an in vivo stroke model.

From: Rapid endothelial cytoskeletal reorganization enables early blood–brain barrier disruption and long-term ischaemic reperfusion brain injury

Figure 1

(a) Representative images of coronal brain sections showing the leakage of two fluorescent tracers Alexa555-dextran (3 kDa, red) and FITC-dextran (2,000 kDa, green) into brain parenchyma at indicated reperfusion (R) time points after 1 h of tFCI. Extravasation of endogenous plasma IgG into the central nervous system was visualized on adjacent sections from the same brains by applying fluorescent secondary antibodies against endogenous mouse IgG molecules (green). MAP2 immunostaining was used to illustrate infarcts in the same brains, as observed in the striatum at 6 h and in the entire MCA territory at 24 h. Scale bar, 1 mm. (b) Volume of leakage of Alexa555-dextran, endogenous IgG and FITC-dextran in sham-operated brains (S) and at 0.5–24 h of reperfusion after tFCI. n=4–5 mice per group. (c) In a separate cohort of mice, extravasation of Alexa555-dextran (3 kDa) and Alexa488-BSA (60–70 kDa) into striatal and cortical parenchyma at 0.5–72 h of reperfusion was quantified by calculating their blood–brain transfer coefficient K i. n=5–6 mice per group. *P≤0.05, **P≤0.01, ***P≤0.001 versus sham. (d–g) tFCI was induced for 1 h in WT or MMP-9−/− mice followed by reperfusion. In separate groups of WT mice, vehicle or the broad-spectrum MMP inhibitor GM6001 was administered as described in Methods. (d) Representative images showing the leakage of Alexa555-dextran (3 kDa, red) and plasma IgG (green) into brain parenchyma at 0.5, 3 and 24 h of reperfusion. MAP2 immunostaining illustrates infarction in the same brains. Scale bar, 1 mm. (e) Volume of leakage of Alexa555-dextran and endogenous IgGs in the same groups. (f) Sensorimotor dysfunction was assessed by the corner test up to 14 d after tFCI and expressed as the number of left body turns made over the course of 10 trials. (g) Brain infarct volumes were calculated on MAP2-stained sections at 1 and 14 d after tFCI. n=6 mice per group. *P≤0.05, **P≤0.01 versus WT. d, days.

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