叔丁基对苯二酚通过HIF-1α/VEGF通路促进小鼠脑梗死后血管新生

Tert-butylhydroquinone promoted angiogenesis through HIF-1α/VEGF pathway after focal cerebral ischemia in mice

目的探讨叔丁基对苯二酚(t BHQ)对小鼠脑梗死后血管新生的影响及作用机制。方法采用电凝法制备小鼠局灶性脑梗死模型(d MCAO)。(1)将野生型小鼠随机分为:假手术组,对照组,小剂量t BHQ组(20mg·kg^-1),中剂量t BHQ组(30mg·kg^-1),大剂量t BHQ组(40mg·kg^-1)。通过行为学评分和测定脑梗死体积挑选合适的剂量;(2)将野生型小鼠和Nrf2基因敲除小鼠随机分为六组:假手术组,对照组,t BHQ组,基因敲除假手术组,基因敲除对照组,t BHQ基因敲除组。各组小鼠测定微血管密度、Brd U^+/CD31^+阳性细胞数及Nrf2、HIF-1α和VEGF蛋白的表达。结果 (1)与对照组相比,大剂量t BHQ组行为学评分明显改善,梗死体积明显减小;(2)在野生型小鼠,t BHQ组比对照组明显增加微血管密度和Brd U+/CD31+阳性细胞数,同时增加HIF-1α/VEGF蛋白的表达;然而,在基因敲除小鼠,基因敲除对照组比对照组微血管密度和HIF-1α/VEGF蛋白表达明显减少,即使t BHQ治疗后,t BHQ基因敲除组微血管密度和HIF-1α/VEGF蛋白也没有增加。结论在d MCAO后,t BHQ延迟治疗能够激活Nrf2信号通路,增加HIF-1α/VEGF蛋白的表达,从而促进脑梗死后血管新生。

Objective We explored whether treatment of tert-butylhydroquinone(t BHQ) could promote angiogenesis after stroke. Method(1) We established 5 experimental groups: sham group, control group, L-t BHQ group(20 mg·kg^-1), M-t BHQ group(30 mg·kg^-1), H-t BHQ group(40 mg·kg^-1). The rotarod test and m NSS were measured on d1, 7, 14, 28. The infarct volume was measured on d3;(2) We used WT mice and Nrf2 knockout mice to establish 6 experimental groups: sham group, control group, t BHQ group, sham Nrf2 knockout group,control Nrf2 knockout group,t BHQ Nrf2 knockout group. The microvessel density and the number of CD31^+/Brd U^+ cells were measured at d14 and d28 by immunofluorescence. The expression of Nrf2, HIF-1α and VEGF in ischemic brain were measured at d14 by western blot. Results Compared with control group, the H-t BHQ group significantly improved the neurological functional deficit, and decreased infarct volume. In WT mice, t BHQ upregulated the microvessel density and the expression of Nrf2, HIF-1α and VEGF, while no improvement was observed in t BHQ Nrf2 knockout mice. Conclusion These results suggested that t BHQ promoted angiogenesis through activating Nrf2 pathway and upregulating HIF-1α/VEGF expression.