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目的对牦牛、迁饲黄牛及低海拔黄牛颈动脉体(CB)形态及CB中低氧相关因子的表达进行比较,探讨高原土生或迁饲动物CB适应慢性低氧的模式。方法采集青海地区海拔3000~4000m的9头牦牛、2500m的9头高山迁饲黄牛及甘肃平原海拔1300米的12头低海拔黄牛的CB,固定、切片、染色后行光学显微镜和电子显微镜比较观察,并对CB中低氧诱导因子-1α(HIF-1α)、一氧化氮合酶(NOS)、瘦素受体(LEPR)、促红细胞生成素(EPO)等低氧相关因子的表达进行免疫组织化学观察。结果相比黄牛,牦牛CB体积较小,不同海拔牦牛的CB大小、形态及主细胞数量差异无显著性,而迁饲黄牛CB体积较低海拔黄牛大。牦牛CB主细胞中明细胞、暗细胞和固缩细胞的数量百分比比例为67.1%∶28.2%∶4.7%,迁饲黄牛为78.5%∶18.6%∶2.9%,低海拔黄牛为87.3%∶10.2%∶2.5%;与低海拔黄牛相似,牦牛CB少部分明细胞胞质透亮,暗细胞胞核染色质较致密并呈粗颗粒状,而迁饲黄牛CB大部分明细胞胞质透亮,暗细胞胞核染色质致密,颗粒稀少。3种牛支持细胞形态差异无显著性。与低海拔黄牛相比,迁饲黄牛CB主细胞的少数核异染色质增多,个别形态异常,胞质内多数细胞器肿胀溶解,残留少量细胞器和致密核心囊泡。3种牛CB中均有不同程度的HIF-1a、NOS、LEPR、EPO的蛋白表达,其中牦牛CB中EPO蛋白表达阳性率较低海拔黄牛明显降低(P<0.05)。结论海拔高度不是影响牦牛颈动脉体大小和主细胞数量的主要因素。迁饲黄牛CB主细胞中细胞类型的比例与牦牛有趋同性改变,但缺氧时行使功能的I型细胞功能系统受损,尚处于低氧环境下的习服阶段。慢性低氧可能主要影响牦牛和迁饲黄牛CB中EPO蛋白表达。
Objective To compare the morphology of carotid body (CB) and the expression of hypoxia related factor (CBO) in yaks, migrating cattle and low altitude cattle, and to explore the mode of CB adaptation to chronic hypoxia in indigenous or migrated animals. Methods The CB of 9 yaks at 3000 ~ 4000m above sea level in Qinghai Province, 9 cattle at 2500m altitude and 12 low altitude cattle at 1300 m altitude in Gansu Plain were collected, fixed, sectioned and stained with light microscope and electron microscope , And the expression of HIF-1α, NOS, LEPR, EPO and other hypoxia-related factors in CB were immunized Histochemical observation. Results Compared with cattle, the yak CB was smaller in size, and there was no significant difference in the CB size, morphology and the number of main cells among the yaks at different altitudes. Yak CB host cells in the percentage of the percentage of bright cells, dark cells and pyknotic cells were 67.1%: 28.2%: 4.7%, 78.5% for cattle: 18.6%: 2.9%, 87.3% for low-altitude cattle: 10.2% : 2.5%. Similar to the low-altitude cattle, a small part of the caking cells of the yak CB translocated the cytoplasm, the dark-colored chromatin was dense and coarse granularity, Chromatin dense, sparsely populated. There was no significant difference in the morphology of three kinds of bovine support cells. Compared with the low-altitude cattle, a few of the nuclear heterochromatin in the main cells of the migrating cattle CB were increased, and some morphological abnormalities were observed. Most organelles in the cytoplasm were swollen and dissolved, leaving a small amount of organelles and dense core vesicles. The protein expression of HIF-1a, NOS, LEPR and EPO in three kinds of bovine CB were all different, and the positive rate of EPO protein in yak CB was significantly lower than that in the lower altitude (P <0.05). Conclusion Altitude is not the main factor affecting body size and host cell number of yak carotid artery. The proportions of cell types in the main CB cells fed to cattle were similar to that of the yaks, but the function of type I cells in hypoxia was impaired and was still in the hypoxic stage of acclimatization. Chronic hypoxia may mainly affect EPO protein expression in yaks and CBs.