Effects of electroacupuncture on the functionality of NG2-expressing cells in perilesional brain tissue of mice following ischemic stroke

Neural/glial antigen 2(NG2)-expressing cells has multipotent stem cell activity under cerebral ischemia.Our study examined the effects of electroacupuncture(EA)therapy(2 Hz,1 or 3 mA,20 minutes)at the Sishencong acupoint on motor function after ischemic insult in the brain by investigating the rehabilitative potential of NG2-derived cells in a mouse model of ischemic stroke.EA stimulation alleviated motor deficits caused by ischemic stroke,and 1 mA EA stimulation was more efficacious than 3 mA EA stimulation or positive control treatment with edaravone,a free radical scavenger.The properties of NG2-expressing cells were altered with 1 mA EA stimulation,enhancing their survival in perilesional brain tissue via reduction of tumor necrosis factor alpha expression.EA stimulation robustly activated signaling pathways related to proliferation and survival of NG2-expressing cells and increased the expression of neurotrophic factors such as brain-derived neurotrophic factor,tumor growth factor beta,and neurotrophin 3.In the perilesional striatum,EA stimulation greatly increased the number of NG2-expressing cells double-positive for oligodendrocyte,endothelial cell,and microglia/macrophage markers(CC1,CD31,and CD68).EA therapy also greatly activated brain-derived neurotrophic factor/tropomyosin receptor kinase B and glycogen synthase kinase 3 beta signaling.Our results indicate that EA therapy may prevent functional loss at the perilesional site by enhancing survival and differentiation of NG2-expressing cells via the activation of brain-derived neurotrophic factor-induced signaling,subsequently ameliorating motor dysfunction.The animal experiments were approved by the Animal Ethics Committee of Pusan National University(approval Nos.PNU2019-2199 and PNU2019-2884)on April 8,2019 and June 19,2019.

Subacute electroacupuncture at Baihui (GV 20) and Dazhui (GV 14) promotes post-stroke functional recovery via neurogenesis and astrogliosis in a photothrombotic stroke mouse model

OBJECTIVE:To investigate the optimal timing and underlying mechanism of electroacupuncture(EA)at Baihui(GV 20)and Dazhui(GV 14)for improved long-term functional recovery after focal cerebral ischemia in a photothrombotic stroke mouse model.METHODS:Totally 50 adult male C57 BL/6 J mice were assigned into 5 groups:(a)the control group,sham-operated mice(n=10);(b)the vehicle group,focal cerebral ischemia induction without EA(n=10);(c)the acute EA group,mice received EA immediately post-ischemia,followed by once-daily treatments for 7 consecutive days(n=10);(d)the subacute EA group,mice received EA 4 days post-ischemia,followed by once-daily treatments for 7 consecutive days(n=10);(e)the delayed EA group.EA stimulation(2 Hz,2 V for 20 min)was applied to acupuncture points(acupoints),Baihui(GV 20)and Dazhui(GV 14),once a day for 7 consecutive days beginning immediately(acute treatment),4 d(subacute treatment)and 10 d(delayed treatment)after focal cerebral ischemia in C57 BL/6 J mice.Behavioral assessments were conducted 21 and 28 d post-ischemia and histopathological analyses were performed 28 days post-ischemia.RESULTS:The subacute EA treatment at Baihui(GV20)and Dazhui(GV 14)significantly improved functional recovery compared to the vehicle group 28 d after ischemic brain injury,although brain atrophy was not reduced.The number of Neu N+and Neu N+/Brd U+cells as well as GFAP intensity in the ipsilateral cortex were significantly increased in the subacute group compared to the vehicle group 28 d post-ischemia.We concluded that EA stimulation 4 d post-ischemia(subacute treatment)enhanced neurogenesis and astrogliosis,likely contributing to long-term functional recovery following focal cerebral ischemia.CONCLUSION:Our findings suggest that the timing of the EA therapy at Baihui(GV 20)and Dazhui(GV 14)determines the therapeutic effects in mice with focal cerebral ischemia induced by photothrombotic occlusion.