Lexiscan can open the blood-brain barrier temporarily and reversibly

Objective: To evaluate the opening level and optimal time window of the blood-brain barrier induced by adenosine A2 receptor agonist (Lexiscan) via dynamic enhanced MRI. Methods: Twenty New Zealand white rabbits were divided into experiment group (group A, n = 10) and control group (group B, n = 10). Rabbits in group A were injected with Lexiscan and rabbits in group B were injected with physiological salt via ear vein, then the coronary scanning was performed. Contrast enhanced MRI was performed at different time points (5, 10, 15, 20 min, and then every 10 min, until 2 h) following the in-fusion of Gd-diethylene triamine pentaacetic acid (DTPA). The signal intensity (SI) of region of interest (ROI) was measured and the percent enhancement of SI was calculated. Evens blue staining results in brain tissues were observed. Pair t test was used to analyze the data. Results: The percent enhancement of SI in group A significantly increased to (40.93 ± 3.70)% at 5 min, reached the maximum of (43.03 ± 3.62)% at 30 min, slowly decreased until 50 min, and got to a stable level at almost 80 min. At each time point, the per-cent enhancement of SI in group A was significantly higher than that in group B (t values: 6.88-20.28, all P < 0.05). The staining was evident in group A. Conclusions: Lexiscan can open blood-brain barrier temporarily and reversibly, and the optimal opening time window is 10-50 min post-injection. (authors)