Figure 4.

Treg treatment protects against tPA thrombolysis-associated haemorrhagic transformation in the embolic mouse model of stroke. Mice were subjected to 3 h MCAO with blood clot. tPA (10 mg/kg) was continuously infused into the femoral vein over 20 min at 3 h after MCAO. Tregs (2 × 10⁶ cells/animal) were transferred to ischaemic recipients immediately after tPA delivery through the femoral vein. PBS served as the control. Sham animals underwent the same anaesthesia and surgical exposure of the arteries without MCAO induction. (A) Representative images of laser speckle cerebral blood flow (CBF) at 5 min, 3 h, 3.5 h, and 24 h after clot MCAO. (B) Quantification of cerebral blood flow. Results are expressed as percentage change from baseline (pre-MCAO). (C) Representative images of the dorsal and ventral surfaces showing intracerebral haemorrhage 1 day after embolic MCAO in mice treated with PBS, tPA+PBS, or tPA+Treg. (D) Quantification of cerebral haemorrhage by spectrophotometric hemoglobin assay 1 day after embolic tMCAO (n = 4/group). (E) Representative images of TTC-stained brain slices showing infarct areas in 6 consecutive coronal sections (1 mm apart) at 1 day after clot stroke. (F) Quantification of infarct volume by TTC staining at 1 day after clot stroke in mice treated with PBS (n = 10), tPA+PBS (n = 10), or tPA+Treg (n = 8). Data are mean ± SE. ^*P ≤ 0.05.