恩格列净通过抑制小胶质细胞激活改善小鼠缺血性脑损伤

Empagliflozin Protects Against Ischemic Brain Injury in Mice by Inhibiting Activation of Microglia

关键词:  脑卒中  高血糖  恩格列净  运动功能损伤

Key words:  stroke  empagliflozin  neurological  dysfunction

摘要:

目的 明确恩格列净对缺血性脑损伤及神经功能损伤的保护作用，并探究潜在的作用机制。方法 利用C57BL/6J小鼠永久性大脑中动脉栓塞建立急性脑缺血模型，术后1 h灌胃给予小鼠不同剂量(10，30 mg·kg⁻¹)恩格列净，术后24 h进行小鼠神经症状评分并检测脑梗死体积。利用小鼠光化学栓塞法(photo-thrombosis，PT)建立局灶性急性脑缺血模型，术后连续7 d或14 d灌胃给予小鼠不同剂量(3，10，30 mg·kg⁻¹)恩格列净，术后每天采用圆筒和网格实验评价小鼠运动感觉功能。在PT造模后连续7 d给予小鼠10 mg·kg⁻¹恩格列净，同时腹腔给予10%葡萄糖溶液，并评价小鼠运动感觉功能，于术后7 d采用免疫荧光检测梗死灶周围小胶质细胞数量及其激活情况。结果 永久性大脑中动脉栓塞术后1 h给予恩格列净显著增加脑梗死体积并加剧神经损伤。在PT造模后连续7 d或连续14 d灌胃给予10 mg·kg^-1恩格列净，可显著降低小鼠错步率和趴壁不对称率，并且给予葡萄糖不能取消其对神经功能的改善作用。然而，在30 mg·kg^-1剂量下，恩格列净加重了PT诱导的小鼠神经功能障碍，给予3 mg·kg^-1恩格列净对PT造模小鼠的神经功能没有影响。此外，10 mg·kg^-1恩格列净可抑制PT造模小鼠缺血区小胶质细胞激活。结论 恩格列净对永久性大脑中动脉栓塞所致小鼠缺血性脑损伤无保护作用；恩格列净以剂量依赖性的方式改善局灶性缺血引起的小鼠神经功能损伤，其神经功能改善作用可能与其降糖效应无关，而与抑制小胶质细胞激活有关。

Abstract:

OBJECTIVE To identify the protective effect of empagliflozin on ischemic brain injury and neurological dysfunction in mice, and further explore its potential mechanism. METHODS Acute cerebral ischemia model was induced by the permanent middle cerebral artery occlusion surgery in C57BL/6J mice. Empagliflozin(10 and 30 mg·kg⁻¹) was administered to mice one hour after the onset of occlusion. Brain infarct volume and neurological defect score were assayed 24 h after surgery. Mice were subjected to photo-thrombosis and further administered with empagliflozin 3, 10, 30 mg·kg⁻¹ intragastricly for either 7 or 14 consecutive days. The grid-walking task and the cylinder task were performed daily to determine the sensory-motor function of the mice. Alternatively, the mice were treated with 10 mg·kg⁻¹ empagliflozin simultaneously with 10% glucose(i.p.) for 7 consecutive days after the photo-thrombosis model to evaluate their motor sensory function. Immunofluorescence staining was used to detect the activation of microglia within the infarct area 7 d after the photo-thrombosis. RESULTS One hour after permanent middle cerebral artery occlusion surgery, gavage of empagliflozin significantly increased the brain infarct volume and neurological dysfunction. While in photo-thrombosis surgery, treatment of empagliflozin(10 mg·kg⁻¹) for consecutive 7 or 14 days significantly decreased the rate of false foot in grid-walking task and the assymetric index in cylinder task. At the dose of 30 mg·kg⁻¹, however, empagliflozin even aggravated photo-thrombosis-induced neurological dysfunction, while the dose of 3 mg·kg⁻¹ showed no effect. Unexpectedly, the protective effect of empagliflozin(10 mg·kg⁻¹) could not be reversed by glucose treatment. The results of immunofluorescence showed that empagliflozin(10 mg·kg⁻¹) significantly alleviated the microglia activation in the ischemic area after the photo-thrombosis operation. CONCLUSION Empagliflozin cannot protect against acute ischemia-induced brain injury in mice. Empagliflozin alleviated ischemia-induced neurological dysfunction with consecutive administration in a dose-related manner. Empagliflozin-conferred neuroprotection may not be attributable to its effects on lowing blood glucose. Alternatively, empagliflozin may play a neuroprotective effect by inhibiting the excessive activation of microglia in ischemic brains.