针刺提高大脑中动脉闭塞大鼠患侧软脑膜侧支代偿效能减轻皮层M5区神经元损伤OA

Objective To observe the dynamic compensatory characteristics of the leptomeningeal collateral(LMC)circulation in the affected hemisphere of rats with right middle cerebral artery occlusion(MCAO),and to investigate the effects of acupuncture on LMC compensatory efficiency and neuronal function in the cortical M5 region.Additionally,to elucidate the neuroprotective mechanism of acupuncture by exploring the temporal pattern of LMC compensation.Methods This study was divided into 2 parts.Part 1:4 male SD rats were randomly selected for monitoring blood perfusion in the affected LMC and cortical M5 region before ischemia,immediately after ischemia,3 h and 12 h post-ischemia using laser speckle contrast imaging.Part 2:90 male SD rats were randomly divided into sham operation,model,sham acupuncture,acupuncture,and butylphthalide groups,with 18 rats in each group.Three hours after modeling,acupuncture was applied to bilateral"Neiguan"(PC6)and"Shuigou"(GV26)or non-acupoints(3 mm below the starting point of bilateral axillary midline and 3 mm beside the apex of coccyx)for 30 min.In the butylphthalide group,butylphthalide injection(2.25 mg/kg)was injected into the tail vein once 3 h after successful modeling.Laser speckle blood flow imaging was used to monitor the changes of blood flow perfusion and LMC vascular diameter in LMC and cortical M5 region at different time points before ischemia,immediately after ischemia and 12 h after ischemia.The percentage of cerebral infarction volume was detected by TTC staining.Modified neuropathy symptom score(mNSS)was used to evaluate neurological function.The grip strength of the contralateral upper limb of the rat was detected by the rat grip tester.The ultrastructure of neurons and mitochondria in the M5 region of the affected cortex was observed by transmission electron microscopy.The positive expression of neuronal nuclear protein(NeuN)in the M5 region of the affected cortex was detected by immunofluorescence staining.The content of adenosine triphosphate(ATP)in the cortex of the affected side was detected by colorimetry.Results Compared with the pre-ischemia state,the blood perfusion in the affected LMC and cortical M5 region were decreased immediately after ischemia(P<0.01).Compared with the immediate ischemia state,the blood perfusion was increased at 3 h post-ischemia(P<0.01,P<0.05).Immediately after ischemia,compared with the sham operation group,the ratio of blood perfusion compared to the baseline level of LMC and cortical M5 in all groups was decreased(P<0.01).At 12 h post-ischemia,the ratio of blood perfusion compared to the baseline level in the LMC and M5 region,and the grip strength of the contralateral upper limb were decreased(P<0.01)in the model group,while the mNSS score and the percentage of cerebral infarction volume were increased(P<0.01).The ultrastructure of neurons and mitochondria in the M5 region of the affected cortex was seriously damaged,and the positive expression of NeuN and the content of ATP in the M5 region were decreased(P<0.01).At 12 h post-ischemia and compared with the model group,the LMC and M5 perfusion ratio,grip strength and the NeuN positive expression and ATP content in the M5 region were significantly increased(P<0.01)in the acupuncture and butylphthalide groups,rather than in the sham acupuncture group,whereas the mNSS score and the percentage of cerebral infarction volume were decreased(P<0.01,P<0.05)in the acupuncture and butylphthalide groups,rather than in the sham acupuncture group.Meanwhile,the ultrastructural damage of neurons and mitochondria was milder in both acupuncture and butylphthalide groups.Conclusion The compensatory efficacy of the affected LMC in MCAO rats increases through blood flow redistribution at 3 h after ischemia,but declines at 12 h.Acupuncture can enhance the LMC compensatory efficiency,improve cortical M5 blood perfusion,and optimize mitochondrial structure and functional homeostasis,thereby exerting neuroprotective effects.