Post-injury berberine treatment attenuated brain edema, blood-brain barrier (BBB) permeability, matrix metalloproteinase (MMP)-9 enzymatic activity, neutrophil infiltration and ICAM expression after TBI.

Berberine (10 mg·kg⁻¹) significantly decreased (A) brain water content and (B) leakage of Evans Blue into the brain and in the ipsilateral hemisphere compared with the vehicle-treated mice. (C) Representative zymography of MMP-9 activity from a sham-injured control, a 10 mg·kg⁻¹ berberine-treated, and a vehicle-treated mouse at 1 day post-TBI including the MMP-9 standard as a positive controls (PC). The gelatinase activity of MMP-9 was significantly decreased in berberine-treated mice compared with vehicle-treated mice. (D) Representative myeloperoxidase (MPO)-stained brain sections from a sham-injured control, a 10 mg·kg⁻¹ berberine-treated, and a vehicle-treated mouse at 1 day post-TBI. The inset is a representative MPO-positive cell at higher magnification. Cell count analysis shows that berberine-treated mice had significantly fewer infiltrating neutrophils than vehicle-treated mice in the cortical contusion margin at 1 day post-TBI. The number of MPO-positive cells is expressed as the mean number per field of view (0.8 mm²). Scale bar, 100 µm. Western blot analysis of (E) claudin-5, (F) zonula occludens 1 (ZO-1), and (G) intercellular adhesion molecule (ICAM)-1 levels in the ipsilateral hemisphere of sham-injured, vehicle-treated, and 10 mg·kg⁻¹ berberine-treated mice at 6 h, 12 h, and 1 day post-TBI. Treatment with 10 mg·kg⁻¹ berberine did not affect TBI-mediated reduced expression of claudin-5 or ZO-1 at any tested time-points but attenuated ICAM-1 expression at 1 day. Values are mean ± SEM; ^*P<0.05, ^***P<0.001 vs. the sham group; ^#P<0.05, ^##P<0.01 vs. the vehicle group as determined by one-way ANOVA (n = 5–7 mice/group for brain water content, Evans Blue amount, MMP-9 activity and n = 4–6 mice/group for all Western blot analysis). Values are presented as means ± SEM; ^#P<0.05 vs. the vehicle group as determined by the Student's t-test (n = 5–6 mice/group for MPO staining).