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目的考察丹酚酸B鼻腔给药后在大鼠海马组织的分布及鼻腔给药对脑缺血损伤大鼠学习记忆能力的影响,并初步探讨其作用机制。方法采用高效液相色谱法检测鼻腔给药后不同时间大鼠海马组织丹酚酸B的浓度;采用四动脉结扎法复制大鼠脑缺血模型,随机分为假手术组、模型组、丹酚酸B鼻腔给药组,于脑缺血后1周开始给药,每天1次,连续3周。采用Morris水迷宫方法,考察丹酚酸B鼻腔给药对脑缺血损伤大鼠空间学习记忆能力的影响。采用甲酚紫(尼氏)染色法,考察丹酚酸B鼻腔给药对脑缺血损伤大鼠海马区形态学特征的影响。采用BrdU标记及免疫组织化学法考察丹酚酸B鼻腔给药对脑缺血损伤大鼠海马区新生神经细胞存活的影响。结果脑内药物浓度测定结果显示丹酚酸B鼻腔给药可在海马组织有一定分布,其峰浓度(C_(max))为(2.47±0.55)μg/g,曲线下面积(AUC)为(336.4±73.0)μg·min/g;Morris水迷宫实验结果显示丹酚酸B鼻腔给药可以降低脑缺血损伤大鼠的平均逃避潜伏期,延长脑缺血损伤大鼠在原平台象限停留时间(P<0.05),增加脑缺血损伤大鼠跨越原平台次数(P<0.05)。形态学结果显示模型组大鼠海马CA1区细胞层数减少,锥体细胞数目明显减少,且排列不规则;与模型组比较,丹酚酸B鼻腔给药组海马形态结构清晰,神经细胞排列较规则,神经元数目明显增多;BrdU标记结果显示脑缺血损伤稳定后假手术组和模型组BrdU阳性细胞数目无明显变化,但丹酚酸B鼻腔给药组BrdU阳性细胞数目显著增多(P<0.01)。结论丹酚酸B鼻腔给药可在海马组织有一定的药物分布,可以明显改善脑缺血损伤导致的学习记忆能力,这种作用可能与直接促进海马神经干细胞增殖有关。
Objective To investigate the distribution of salvianolic acid B in rat hippocampus after nasal administration and the effect of nasal administration on the learning and memory abilities of rats with cerebral ischemia injury and to explore its mechanism. Methods The concentration of salvianolic acid B in the hippocampus of rats was measured by high performance liquid chromatography (HPLC). The model of cerebral ischemia was established by four-artery ligation. The rats were randomly divided into sham operation group, model group, Acid B nasal administration group, one week after cerebral ischemia administration, once a day for 3 weeks. Morris water maze method was used to investigate the effect of salvianolic acid B nasal administration on spatial learning and memory in rats with cerebral ischemia. The influence of salvianolic acid B nasal administration on morphological characteristics of hippocampus in cerebral ischemic rats was investigated by cresyl violet (Nissl) staining. BrdU labeling and immunohistochemistry were used to investigate the effect of salvianolic acid B nasal administration on the survival of newborn neurons in hippocampus of rats with cerebral ischemia. Results The intracerebral drug concentration measurement showed that salvianolic acid B could be distributed in the hippocampus with a peak concentration (C max) of (2.47 ± 0.55) μg / g and the area under the curve (AUC) was ( 336.4 ± 73.0) μg · min / g. Morris water maze test showed that intranasal administration of salvianolic acid B could reduce the average escape latency of rats with ischemic insult and prolong the retention time in the original platform quadrant of cerebral ischemic injury rats (P <0.05), and increased the number of crossing the primary platform in rats with cerebral ischemia (P <0.05). Morphological results showed that in hippocampal CA1 region, the number of cells and the number of pyramidal cells in hippocampal CA1 region of model group decreased significantly, and the arrangement was irregular. Compared with model group, the morphology and structure of hippocampus of salvianolic acid B nasal administration group were clear The numbers of BrdU positive cells in the sham operation group and the model group were not significantly changed after BrdU labeling. However, the number of BrdU positive cells in the salvianolic acid B nasal administration group was significantly increased (P < 0.01). Conclusion Nasal administration of salvianolic acid B may have certain drug distribution in the hippocampus, which can obviously improve the learning and memory abilities induced by cerebral ischemia injury. This effect may be related to directly promoting the proliferation of neural stem cells in hippocampus.