Stroke is a cardiovascular disease that seriously endangers human health, which is characterized by high prevalence, disability and mortality rates. Peony bark is the dried root bark of peony in the buttercup family, which has the effect of clearing heat and cooling blood, activating blood circulation and resolving blood stasis. Paeonol (PAE) is the main active ingredient of peony bark, has been confirmed to have neuroprotective effect under hypoglycemia and hypoxia conditions.

To observe the effect and neurobiological mechanism of gastric administration of paeonol solution on improving behavioral dysfunction caused by middle cerebral artery occlusion (MCAO) , a kind of stroke, in a mouse model.

The study was conducted from December 2019 to December 2021. Twenty SPF male C57BL/6 mice were randomized into SHAM group (n=10) and model group (MCAO group, n=10) . The MCAO model was formed by intraluminal suture method. After 24 hours of modeling, the neurological function of each group was evaluated by Longa Score. Laser Speckle Contrast Imaging was used to monitor the changes of cerebral blood flow after MCAO. TTC staining was used in the pathological examination of cerebral infarction in MCAO mice. For investigating the protective effect of PAE on behavioural dysfunction of MCAO mice, 50 SPF male C57BL/6 mice were randomly grouped into SHAM group (n=10) , model+corn oil group (n=20) , and model+PAE group (n=20) . After the verification of model stability at 24 hours following the modeling, the model+PAE group received intragastric administration of PAE and corn oil solution in a concentration of 100 mg·kg^-1· d^-1, and the other two groups were gavaged with equal amounts of corn oil. Then on the 28th day after of modelling, survival curve was plotted to assess the survival status of mice in the three groups; the neurological recovery of mice was determined using the Longa Score; the area of cerebral infarction was examined by Nissl staining. The behavioural changes in motor sensory function were tested at five time points: the day before modeling, and 7, 14, 21 and 28 days after modelling. For exploring the mechanism of PAE improving behavioural dysfunction in MCAO mice, 30 SPF male C57BL/6 mice were randomly divided into SHAM group (n=6) , model+corn oil group (n=12) and model+PAE group (n=12) . After verifying the model stability at 24 hours following the modeling, the model+PAE group received intragastric administration of PAE and corn oil solution in a concentration of 100 mg·kg^-1· d^-1, and the other two groups were gavaged with an equal amount of corn oil. The expression of interleukin 1β (IL-1β) protein in the striatum of mouse brain was measured by Western blotting on the second day after modelling to investigate whether PAE could reduce the inflammatory response in the brain during the acute period. The expression of ionized calcium-binding adapter molecule 1 (IBA1) and glial fibrillary acidic protein (GFAP) in the penumbra was measured by immunofluorescence on the 14th day after modelling.

The 28-day survival rate was 66.47% for the model+corn oil group, and 81.43% for model+PAE group. Log-rank test showed that the 28-day survival curve significantly differed across SHAM group, model+corn oil group, and model+PAE group (χ²=1.436, P<0.05) The Longa Score was lower in model+PAE group than in model+corn oil group on the 28th day after modelling (P<0.05) . The differences in the expression levels of IBA1 and GFAP in brain tissues of the three groups were statistically significant (P<0.05) . Specifically, the expression levels of IBA1 and GFAP in brain tissues in SHAM group were lower than those of the other two groups (P<0.05) . The expression levels of IBA1 and GFAP in brain tissues in model+PAE group were lower than those in model+corn oil group (P<0.05) . On the second day after modelling, model+corn oil group had higher expression level of IL-1β in striatum than both SHAM group and model+PAE group (P<0.05) .

PAE could control the inflammatory response in the acute stage, reduce the area of acute cerebral infarction, prolong the survival time and improve the motor sensory function in the mouse model of MCAO.

中风是严重危害人体健康的心脑血管系统疾病之一，具有高患病率、高致残率和高致死率的特征。牡丹皮是毛茛科植物牡丹干燥根皮，具有清热凉血、活血化瘀之功效。丹皮酚是牡丹皮的主要活性成分，已有研究证实在缺糖缺氧条件下，丹皮酚对神经元有一定保护作用。

观察丹皮酚对大脑中动脉缺血（MCAO）模型小鼠的干预效果，探究丹皮酚溶液灌胃在治疗中风行为功能障碍的神经生物学机制。

本研究时间为2019年12月—2021年12月。缺血性中风模型的建立与评价：将20只SPF级雄性C57BL/6小鼠，采用随机数字表法分成假手术组（n=10）、模型组（MCAO组，n=10），采用线栓法制成小鼠MCAO模型，造模24 h后，通过Longa评分评价各组小鼠神经功能受损情况；激光散斑血流成像系统监测各组小鼠在MCAO术后大脑血流改变状况；对MCAO术后的小鼠进行TTC染色，在病理上观察小鼠大脑的损伤情况。探究丹皮酚对MCAO小鼠的行为功能保护作用：将50只SPF级、雄性C57BL/6小鼠进行随机分组：假手术组（n=10）、模型+玉米油组（n=20）、模型+丹皮酚组（n=20）。造模后24 h，验证模型稳定后，模型+丹皮酚组用丹皮酚玉米油溶液灌胃，给药浓度为100 mg·kg^-1· d^-1，其余组灌服等量玉米油。在造模28 d后，统计三组小鼠的存活情况，绘制生存曲线；使用Longa评分判断小鼠神经功能恢复情况；尼氏染色法检测小鼠大脑梗死面积；行为学测试小鼠在造模前及造模后7、14、21、28 d 5个时间点的运动感觉功能改变。探究丹皮酚对MCAO小鼠行为功能改善的机制：随机将30只SPF级、雄性C57BL/6小鼠分成假手术组（n=6）、模型+玉米油组（n=12）、模型+丹皮酚组（n=12）。造模后24 h，验证模型稳定后，药物组用丹皮酚玉米油溶液灌胃，给药浓度为100 mg·kg^-1·d^-1，其余组灌服等量玉米油。造模后2 d，用Western blotting法测定小鼠大脑纹状体白介素1β（IL-1β）蛋白表达情况，探究急性期内丹皮酚是否能降低大脑炎性反应；造模后14 d，采用免疫荧光法检测小鼠大脑半暗带离子钙结合衔接分子1（IBA1）、胶质纤维酸性蛋白（GFAP）的表达。

模型+玉米油组小鼠干预28 d的生存率为66.47%，丹皮酚组小鼠生存率为81.43%。Log-rank检验结果显示，三组小鼠干预28 d的生存曲线比较，差异有统计学意义（χ²=1.436，P<0.05）。造模28 d后，模型+丹皮酚组Longa评分低于模型+玉米油组（P<0.05）。三组小鼠造模后14 d脑组织中IBA1、GFAP表达水平比较，差异有统计学意义（P<0.05）；模型+玉米油组、模型+丹皮酚组小鼠造模后14 d脑组织中IBA1、GFAP表达水平高于假手术组（P<0.05）；模型+丹皮酚组小鼠造模后14 d脑组织中IBA1、GFAP表达水平低于模型+玉米油组（P<0.05）。模型+玉米油组小鼠造模后2 d纹状体IL-1β蛋白表达水平高于假手术组（P<0.05）；模型+丹皮酚组小鼠造模后2 d纹状体IL-1β蛋白表达水平低于模型+玉米油组（P<0.05）。

丹皮酚可控制MCAO模型中小鼠在急性阶段的发症反应，减少了小鼠急性脑梗死面积，延长了小鼠生存期、改善了其运动感觉功能。