“Baihui” (DU20)‐penetrating “Qubin” (GB7) acupuncture on blood–brain barrier integrity in rat intracerebral hemorrhage models via the RhoA/ROCK II/MLC 2 signaling pathway

Abstract

Abstract Background Blocking the RhoA/ROCK II/MLC 2 (Ras homolog gene family member A/Rho kinase II/myosin light chain 2) signaling pathway can initiate neuroprotective mechanisms against neurological diseases such as stroke, cerebral ischemia, and subarachnoid hemorrhage. Nevertheless, it is not clear whether and how disrupting the RhoA/ROCK II/MLC 2 signaling pathway changes the pathogenic processes of the blood–brain barrier (BBB) after intracerebral hemorrhage (ICH). The present investigation included the injection of rat caudal vein blood into the basal ganglia area to replicate the pathophysiological conditions caused by ICH. Methods Scalp acupuncture (SA) therapy was performed on rats with ICH at the acupuncture point “Baihui”‐penetrating “Qubin,” and the ROCK selective inhibitor fasudil was used as a positive control to evaluate the inhibitory effect of acupuncture on the RhoA/ROCK II/MLC 2 signaling pathway. Post‐assessments included neurological deficits, brain edema, Evans blue extravasation, Western blot, quantitative polymerase chain reaction, and transmission electron microscope imaging. Results We found that ROCK II acts as a promoter of the RhoA/ROCK II/MLC 2 signaling pathway, and its expression increased at 6 h after ICH, peaked at 3 days, and then decreased at 7 days after ICH, but was still higher than the pre‐intervention level. According to some experimental results, although 3 days is the peak, 7 days is the best time point for acupuncture treatment. Starting from 6 h after ICH, the neurovascular structure and endothelial cell morphology around the hematoma began to change. Based on the changes in the promoter ROCK II, a 7‐day time point was selected as the breakthrough point for treating ICH model rats in the main experiment. The results of this experiment showed that both SA at “Baihui”‐penetrating “Qubin” and treatment with fasudil could improve the expression of endothelial‐related proteins by inhibiting the RhoA/ROCK II/MLC 2 signaling pathway and reduce neurological dysfunction, brain edema, and BBB permeability in rats. Conclusion This study found that these experimental data indicated that SA at “Baihui”‐penetrating “Qubin” could preserve BBB integrity and neurological function recovery after ICH by inhibiting RhoA/ROCK II/MLC 2 signaling pathway activation and by regulating endothelial cell–related proteins.

Keywords

• blood–brain barrier
• caveolae
• intracerebral hemorrhage
• RhoA/ROCK II/MLC 2 signaling pathway
• scalp acupuncture