Objective: To investigate whether blood-brain barrier served a key role in the edema-relief effect of bloodletting puncture at hand twelve Jing-well points in traumatic brain injury and the potential molecular signalling pathways.
Methods: Adult male Sprague-Dawley rats were assigned to the sham-operated (sham), traumatic brain injury, and bloodletting puncture (bloodletting) groups (n=24 per group) using a randomized number table. The traumatic brain injury model rats were induced by cortical contusion and then bloodletting puncture were performed at hand twelve Jing-well points twice a day for 2 days. The neurological function and cerebral edema were evaluated by modified neurological severity score (mNSS), cerebral water content, magnetic resonance imaging and hematoxylin and eosin staining. Cerebral blood flow was measured by laser speckles. The protein levels of aquaporin 4 (AQP4), matrix metalloproteinases 9 (MMP9) and mitogen-activated protein kinase pathway (MAPK) signaling were detected by immunofluorescence staining and Western blot.
Results: Compared with traumatic brain injury group, bloodletting puncture improved neurological function at 24 and 48 h, alleviated cerebral edema at 48 h, and reduced the permeability of blood-brain barrier induced by traumatic brain injury (all P<0.05). The AQP4 and MMP9 which would disrupt the integrity of blood-brain barrier were downregulated by bloodletting puncture (P<0.05 or P<0.01). In addition, the extracellular signal-regulated kinase (ERK) and p38 signaling pathways were inhibited by bloodletting puncture (P<0.05).
Conclusions: Bloodletting puncture at hand twelve Jing-well points might play a significant role in protecting blood-brain barrier through regulating the expressions of MMP9 and AQP4 as well as corresponding regulatory upstream ERK and p38 signaling pathways. Therefore, bloodletting puncture at hand twelve Jing-well points may be a promising therapeutic strategy for traumatic brain injury-induced cerebral oedema.