脑源性神经营养因子在牦牛与黄牛端脑不同区域的表达与分布

Expression and distribution of brain-derived neurotrophic factor in different cerebrum regions of yak and cattle

目的探讨高原牦牛与平原黄牛端脑中脑源性神经营养因子(BDNF)表达与分布,探讨BDNF功能发挥与高原低氧适应性之间的关联。方法选取牦牛和黄牛各5只,应用Real-time PCR、Western blotting及免疫组织化学技术对BDNF在牦牛和黄牛端脑的额叶、颞叶、顶叶、枕叶、大脑白质以及海马中的含量与分布进行了定量与定性分析。结果Real-time PCR结果表明,在牦牛与黄牛端脑中,BDNF mRNA均在颞叶皮质中的表达量最高,海马次之,其后依序为顶叶皮质,枕叶皮质和额叶皮质,在大脑白质中的表达量最低。Western blotting结果表明,BDNF蛋白在牦牛颞叶皮质中含量最高,海马次之,其他组织含量由高到低依次为顶叶皮质、额叶皮质、大脑白质,枕叶皮质中含量最低。BDNF蛋白在黄牛端脑颞叶皮质中含量最高,海马次之,其余组织含量由高及低依次为顶叶皮质、枕叶皮质、额叶皮质,大脑白质中蛋白含量最低。免疫组织化学结果表明,BDNF蛋白在牦牛和黄牛端脑中的阳性表达情况基本相似,主要分布在额叶皮质、颞叶皮质、顶叶皮质、枕叶皮质的颗粒细胞和神经胶质细胞,大脑白质的神经胶质细胞以及海马的锥体细胞层和多形细胞层,在端脑皮质区的马丁诺提细胞和海马的分子细胞层中有少量分布。结论BDNF mRNA和蛋白在牦牛和黄牛端脑不同区域中均有表达,但表达量存在差异,推测与端脑不同分区的特定功能密切相关。牦牛端脑中的表达水平除枕叶皮质外,均高于黄牛,推测与其生存的高原低氧环境有关,BDNF在动物机体适应低氧环境过程中可能发挥着增强低氧耐受性和保护机体内环境稳态等重要功能。

Objective To clarify the expression and distribution of brain-derived neurotrophic factor(BDNF)in the cerebrum of plateau yaks and cattle,and to explore the relationship between BDNF function and the adaptability of altitude hypoxia.Methods Five yaks and five cattles were selected.The content and distribution of BDNF in frontal lobe,temporal lobe,parietal lobe,occipital lobe,cerebrum white matter and hippocampus of yak and cattle were analyzed by Real-time PCR,Western blotting and Immunohistochemistry.Results Real-time PCR result showed that BDNF mRNA expression in the cerebrum of yaks and cattles was highest in temporal cortex,followed by hippocampus,parietal cortex,occipital cortex and frontal cortex,and lowest in white matter.Western blotting results showed that the content of BDNF protein in the cerebrum of yaks was the highest in temporal cortex,followed by hippocampus.The content of BDNF protein in other tissues was parietal cortex,frontal cortex and cerebrum white matter,and the content of BDNF protein was the lowest in occipital cortex.The content of BDNF protein intlecerebrum of cattles was the highest in the temporal cortex,followed by the hippocampus.The content of BDNF protein in other tissues was parietal cortex,occipital cortex and frontal cortex in descending order,and the protein content in cerebrum white matter was the lowest.Immunohistochemical results showed that the positive expression of BDNF protein in the cerebrum of yaks and cattles was basically similar,mainly distributed in the granulosa cells and glial cells in the frontal cortex,temporal cortex,parietal cortex and occipital cortex,glial cells in cerebrum white matter,pyramidal cell layer and polyform cell layer in the hippocampus.There was the small amount of distribution in Martinotti cells and the molecular layer of hippocampus in the cerebral cortex.Conclusion BDNF mRNA and protein are distributed and expressed in different brain regions of yaks and cattles,but the expression level different,which is speculated to be closely related to the specific functions of different cerebrum regions.The expression level of the cerebrum of yak is higher than that of cattle except occipital cortex,suggesting that it is related to the altitude hypoxic environment.BDNF may play an important role in enhancing hypoxic tolerance and protecting internal environmental homeostasis in the process of animal adaptation to hypoxic environment.