| Mitochondrion is where ATP is generated via oxidation and phosphorylation, which is the body's energy plant. A growing number of researches suggest that it participates into the regulation of various physiological and metabolic processes. In order to study the roles of mitochondrial copy number and angiogenesis related genes in plateau environment adaptability of animals, this study, with Rongchang pigs born in normal plain ?n=3? and Rongchang pigs born in a condition that the mother pigs were pregnant in normal plain and were transferred to plateau environment before delivery ?n=3? as the research materials, adopted the real-time fluorescence quantitative ?qPCR? assay to determine mitochondrial copy number and expressions of energy metabolism related genes in seven tissues ?heart, liver, lungs, kidneys, brain, eye muscles and waist muscles?, to explore the molecular mechanism of animals to adapt to the plateau environment.Two-factor variance analysis results showed that both plateau environment (F= 226.87,p= 5.89×10-15) and different tissues (F= 212.25, p=5.25×10-22) could significantly affect the mitochondrial copy number, and there was a significant interaction effect between elevation and tissues (F=38.89. p=1.87×10-12). Further analysis on the distribution law of mitochondrial copy number in different Tissues found that in the plain-born Rongchang pigs, the largest mitochondrial copy number was found in the eye muscles, while in plateau-born Rongchang pigs, the largest mitochondrial copy number was found in the heart. By independent samples T test, except heart tissue, which was not different between plain-born and plateau-born Rongchang pigs (t-0.32, p= 7.62× 10-1). plateau-born Rongchang pigs were lower than plain-born Rongchang pigs in the rest 6 tissues (brain (t= 17.59. p= 6.13×10-5), lungs (t=3.10. p= 3.61×10-2), liver (t= 3.30, p= 3.99× 10-2)), kidneys (t= 3.30,p= 3.99× 10-2), eye muscle ?t= 31.86,p= 5.79x 10'6?, waist ?t= 10.39, p= 4.84×104?). The obvious decrease of copy number in plateau-born Rongchang pigs may be related to mitochondrial autophagy after damage.In seven tissues ?heart, liver, lungs, kidneys, brain, eye muscles and waist muscle?, expression of mitochondrial genes ?COX1. ND1 and ATP6? in plateau-born Rongchang pigs were higher than that of plain-born Rongchang pigs. It is speculated that energy synthesis efficiency was improved in low-oxygen plateau environment, which caused up-regulated expression of mitochondrial genes. Nuclear gene results showed expression of VEGF gene was up-regulated in the heart, lungs, muscles and brain tissues. It is speculated that these tissues have to promote angiogenesis in low-oxygen plateau environment. Expression of ET1 gene was upregulated in the brain, lungs and kidneys, which was related to maintenance of vascular homeostasis. HIF-1? gene was sensitive to changes of oxygen, which promoted the body to adapt to the low-oxygen plateau environment through regulating the expression of other genes.Expressions of 8 energy metabolism-related genes were analyzed and amplification. Results showed expressions of COX1 (r= 0.399,p=8.9×10-3) and HIF-1?(r= 0.550,p= 1.60×10-4) were significantly negatively correlated with mtDNA copy number; expressions of ND1 (r= 0.317,p= 4.0×10-2), ATP6 (r= 0.333,p= 3.1×10-2) and ET1 (r= 0.165,p= 2.97×10-2) were extremely significantly negatively correlated with mtDNA copy number; it is speculated that the mitochondria that suffered oxidative damage in plateau environment were cleared through mitochondrial autophagy, thus the copy number was reduced, and energy synthesized by mitochondria was decreased; so the expressions of energy metabolism related genes were up-regulated in order to meet the needs of the body for energy.The above research results showed that under plateau environment, animal mitochondria with oxidative damage were cleaned up by mitochondrial autophagy, thus showing the copy number of animal mitochondria in plateau was lower than that in plain environment. In low oxygen plateau environment, the oxygen content animals acquire were decreased while the energy mitochondria synthesized was reduced. In order to meet the needs of the body for energy, genes related to angiogenesis regulation were up-regulated. This research explored changes of mitochondrial copy number in Rongchang pigs, to provide basic inforation for livestock to adapt to the plateau production environment. |
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