黄芩茎叶总黄酮对大鼠大脑海马区微血管和血脑屏障缺血再灌注损伤的预防作用

目的 探讨黄芩茎叶总黄酮（SSTF）对脑缺血再灌注海马区微血管、血脑屏障（BBB）损伤的预防性保护作用。 方法 SD大鼠90只,随机分为假手术组（sham组）、模型组（IR组）和SSTF预处理组，造模前1周SSTF各组灌胃给药，低、中、高剂量组分别给50、100、200 mg/(kg·d)，共7d。IR组和SSTF各组制作脑缺血再灌注模型，术后评价神经功能缺损变化,干湿重法和伊文思蓝法检测脑组织含水量和微血管通透性，单宁酸 氯化铁媒染（TA-Fe）法显示并观测大鼠微血管密度(MVD)和微血管面积比(MVA)，Real-time PCR法检测水通道蛋白4（AQP4） mRNA的表达水平,电镜观察血脑屏障完整性。 结果 SSTF各组与IR组比,神经功能缺损评分、脑组织含水量、微血管通透性明显降低（P＜0.01，P＜0.05）,MVD、MVA增加（P＜0.01）, AQP4 mRNA表达增强(P＜0.01)，BBB损伤不同程度减轻，内皮细胞肿胀渐消退，紧密连接松解好转，基膜渐连续、清晰，胶质细胞足板胞质溶解减轻，渐接近正常；SSTF 中、高组上述表现较SSTF 低组好转的更明显（P<0.01），SSTF 中组与SSTF 高组比较差异无统计学意义（P＞0.05）。 结论 SSTF干预对海马区微血管、血脑屏障和神经损伤有预防性保护作用，其作用机制可能是通过增加有效微血管再通数量，维持血脑屏障完整和功能,减轻脑水肿实现的。SSTF的有效预防剂量为100mg/(kg·d)。

Scutellaria baicalensis stem leaf flavonoids exerts protective effect on ischemia reperfusion injury of microvessel and brain blood barrier in cerebral hippocampus

Objective To explore the preventive protective effects on ischemia reperfusion injury of microvessels and blood brain barrier(BBB) in cerebral hippocampus with scutellaria baicalensis stem leaf total flavonoids (SSTF). Methods Ninety SD rats were assigned randomly into sham operation, ischemia reperfusion, and SSTF pretreated groups. The SSTF group rats were administrated with SSTF intragastrically one week before animal model-making. Low, medium and high dose groups were administrated with 50, 100, 200 mg/(kg ·d), respectively, for 7 days. The model group and SSTF group animals were remodelled into focal ischemia reperfusion models. Changes of neurological defects were evaluated. Postoperatively, water contents and microvascular permeability in brain tissue were detected with wet weight methods and Evans blue (EB) methods. The microvessel density (MVD) and microvessel area ratio(MVA) were observed with tannic acid-ferric chloride mordant dyeing methods (TA-Fe). The change of aquaporin 4(AQP4) mRNA expression was assessed by Real-Time PCR. The ultrastructural integrity of the blood brain barrier was observed under an electron microscope. Results The neurological function defect scale, water content in brain tissue and microvascular permeability in each SSTF group were significantly reduced compared with IR groups（P＜0.01，P＜0.05. The MVD and MVA were obviously increased (P＜0.01), the expression of AQP4 was reduced significantly (P＜0.01), the BBB injuries were alleviated in various degrees, the endothelial cells swelling gradually disappeared, the unloosed tight junction also gradually reclosed and recovered into a normal status, the basal membrane gradually returned into continuous and clear, and the gliacyte cytoplasm dissolving in pedal plate was alleviated and gradually turned close to normal status. While the above alleviate improvements in SSTF M and SSTF H groups were more conspicuous than that in SSTF L group (P<0.01), there was no significant difference between SSTF M and H groups (P>0.05). Conclusion Cerebral ischemia reperfusion can lead the hippocampus microvessel and blood brain barrier to be injured, and SSTF intervention can exert preventive protective effects on cerebral hippocampus tissue. The functional mechanism may carry out effectively by increasing the number of microvascular recanalization, by maintaining the microvessel and brain blood barrier to be in intact status and in normal function, as well as by relieving cerebral edema. It is proved that the optimal effective prevention dose of SSTF is 100mg/(kg·d).