【作者】 齐新章；

【导师】 魏登邦；

【作者基本信息】 青海大学 ， 动物营养与饲料科学， 2009， 硕士

【摘要】 为了探讨高原鼢鼠和高原鼠兔心脏对低氧环境的适应机制,以Sprague-Dawley (SD)大鼠为对照,称重计算三者的心脏/体重比(HW/BW)、右心室/左心室+室间隔重量比[RV/(LV+S)];应用免疫组织化学方法测定心肌微血管密度(MVD);通过显微体视学技术比较心肌线粒体的面数密度(NA)、体密度(VV)、面密度(SV)、比表面(δ);用分光光度法测定心肌中的肌红蛋白(Mb)含量、乳酸(LD)含量和乳酸脱氢酶(LDH)活力;聚丙烯酰胺凝胶电泳观察心肌LDH同工酶谱;用real-time PCR检验低氧诱导因子-1α(HIF-1α)、Mb、血管内皮生长因子165(VEGF165)、LDH-A和LDH-B基因在心肌内mRNA水平的表达。结果显示:高原鼢鼠和高原鼠兔HW/BW显著大于SD大鼠(P<0.05),RV/(LV+S)显著小于SD大鼠(P<0.05)。高原鼢鼠、高原鼠兔和SD大鼠心肌线粒体NA依次递减(P<0.05);高原鼢鼠线粒体VV显著低于高原鼠兔和SD大鼠(P<0.05),高原鼠兔与SD大鼠之间没有明显差异;高原鼢鼠线粒体SV显著高于SD大鼠(P<0.05),与高原鼠兔相比无明显差异;高原鼠兔和SD大鼠的线粒体δ无显著差异,但均明显低于高原鼢鼠(P<0.05)。高原鼢鼠和高原鼠兔心肌HIF-1α在mRNA水平的表达无明显差异,高原鼠兔与SD大鼠无明显差异,高原鼢鼠的表达显著高于SD大鼠(P<0.05)。高原鼢鼠和高原鼠兔心肌Mb mRNA含量显著高于SD大鼠(P<0.05),二者无明显差异;高原鼢鼠和高原鼠兔心肌Mb含量显著高于SD大鼠(P<0.05)。高原鼢鼠心肌VEGF165 mRNA含量显著低于SD大鼠(P<0.05),高原鼠兔表达量居中,与二者无显著差异;高原鼢鼠、高原鼠兔和SD大鼠心肌微血管密度依次降低(P<0.05)。高原鼢鼠和高原鼠兔心肌LDH-A和LDH-B在mRNA水平的表达均显著高于SD大鼠,其中高原鼠兔LDH-B mRNA的表达显著高于高原鼢鼠。高原鼢鼠心肌LD含量显著高于高原鼠兔和SD大鼠(P<0.05);两种高原动物心肌LDH活力显著低于SD大鼠(P<0.05)。同工酶谱显示,高原鼢鼠、高原鼠兔和SD大鼠的LDH中H亚基所占比例依次递减。以上结果表明,高原鼢鼠和高原鼠兔心脏表现出一些相同或相似的特征,这些特征有利于在低氧条件下提高心脏泵血能力、增加氧气从血液到线粒体的弥散效率、氧气的利用效率和低氧应激能力。但是,部分指标又表现出明显的差异,可能是由不同生境和习性造成的。更多还原

【Abstract】 Plateau zokor (Myospalax rufecens baileyi) and plateau pika (Ochotona curzniae) are native to the Qinghai-Tibet plateau. To study their adaptive mechanisms, the ratios of heart weight to body weight (HW/BW) and right to left ventricular plus septum weights [RV/(LV+S)] were determined; the microvessel density (MVD) of cardiac muscle were measured by immunohistochemical staining; the numerical density on area (NA), volume density (VV), specific surface (δ), and surface density (SV) of mitochondria were obtained by microscopy and stereology; the content of myoglobin (Mb), lactic acid (LD) and the activity of lactate dehydrogenase (LDH) in cardiac muscle were analyzed by spectrophotometer; the expression levels of gene Hypoxia-inducible factor-1α( HIF-1α) , Mb, Vascular endothelial growth factor 165(VEGF165), LDH-A and LDH-B were detected by real-time PCR.The results showed that the HW/BW of plateau zokor [(4.55±0.26)%] and plateau pika [(4.41±0.38)%] were significantly greater than that of Sprague-Dawley (SD) rat [(3.44±0.41)%] (P<0.05), but the RV/(LV+S) [(22.04±1.98)%, (25.53±3.41)%] were smaller than that of SD rat [(44.23±3.87)%] (P<0.05). The NA of cardiac muscle was 0.768±0.123 in SD rat, 0.868±0.159 in plateau pika and 1.012±0.133 in plateau zokor. The VV of mitochondria in plateau zokor (0.272±0.045) was significantly lower than those in plateau pika (0.343±0.039) and SD rat (0.321±0.048) (P<0.05), while theδof mitochondria in plateau zokor (9.409±1.238) was higher than those of plateau pika and SD rat (6.772±0.892 and 7.287±1.373) (P<0.05). The SV of mitochondria in plateau pika (2.322±0.347) was not obviously different from that of plateau zokor (2.468±0.380) and SD rat (2.227±0.377), but that of plateau zokor was significantly higher than that of SD rat (P<0.05). The expression level of gene HIF-1αin cardiac muscle of plateau pika (0.45±0.06) had no significant different from plateau zokor (0.51±0.08) and SD rat (0.38±0.05), but that of plateau zokor was obviously higher than that of SD rat (P<0.05). The expression level of Mb mRNA in cardiac muscle of plateau zokor (0.98±0.03) was notably lower than that of pika (1.15±0.39) which was also notably lower than that of SD rat (1.25±0.72) (P<0.05). The contents of Mb in cardiac muscle of plateau zokor [(763.33±88.73) nmol/g] and plateau pika [(765.96±28.47) nmol/g] were significantly higher than that of SD rat [(492.38±72.14) nmol/g] (P<0.05). The expression level of gene VEGF165 in cardiac muscle of plateau zokor (1.52±0.07) was significantly lower than that of SD rat (1.76±0.17), which of plateau pika (1.64±0.08) was slightly higher than plateau zokor and lower than SD rat but the MVD of the cardiac muscle of plateau zokor (2990.643±389.888) was notably higher than plateau pika (2002.888±367.466) which was also notably higher than SD rat (1688.631±250.253). Plateau zokor (1.423±0.031 and 1.167±0.079) and plateau pika (1.305±0.052 and 1.422±0.025) had great higher expression levels of gene LDH-A and LDH-B in cardiac muscle than those in SD rat (1.128±0.164 and 1.023±0.098) (P<0.05), while the contents of LDH-B mRNA in cardiac muscle of plateau pika was significantly higher than that of plateau zokor. The content of LD in plateau zokor [(0.57±0.06) mmol/L] was obviously higher than that of plateau pika [(0.45±0.06) mmol/L] and SD rat [(0.48±0.02) mmol/L] (P<0.05), and the activity of LDH in plateau zokor [(16.90±2.00) U/mL] and plateau pika [(20.55±2.46) U/mL] were significantly lower than that of SD rat [(38.26±6.78) U/mL] (P<0.05). The percentage of LDH-H in cardiac muscle decreased in order in plateau zokor, plateau pika and SD rat.In conclusion, there were some features were same or similar in the heart of plateau zokor and plateau pika, that made their heart could pump more blood, increase the diffusion efficiency of oxygen from blood to mitochondria, use the oxygen more effectively and have a higher stress ability. However, they were very differently from each other in some ways. It should because of their different habitats and habits.更多还原