Effects of Aging on Expression of Mic60 and OPA1 and Mitochondrial Morphology in Myocardium of Tibetan Sheep

SIMPLE SUMMARY: Mitochondria play a crucial role in the adaptation to high altitude hypoxia environment in Tibetan sheep, and the changes of its morphology and structure directly affect its function. OPA1 and Mic60 are important mitochondria-shaping proteins that work together to regulate the morphology of mitochondrial inner membrane and cristae. It has been shown that aging affects the expression of OPA1 and Mic60 in mice, but it has not been investigated in sheep and hence it is not known whether it might affect the ultrastructure of mitochondria. In this context, reverse transcription-quantitative PCR (RT-qPCR), enzyme-linked immunosorbent assay (ELISA) and immunohistochemistry method were used to measure the expression of Mic60 and OPA1 genes and proteins in myocardium of adult and aged Tibetan sheep, and the ultrastructure of mitochondria were compared by transmission electron microscope. The results suggest that aging can reduces the expression of Mic60 and OPA1 genes and OPA1 protein, which can affect the mitochondrial function. ABSTRACT: In order to investigate the effects of aging on the expression of Mic60 and OPA1 and mitochondrial morphology in plateau animals, the expression of Mic60 and OPA1 genes and proteins, and the morphology of mitochondria in the myocardium of adult and aged Tibetan sheep were investigated. The expression of Mic60 and OPA1 genes and OPA1 protein were higher (p < 0.05) in the myocardium of adult Tibetan sheep than in those of the aged ones. The number of mitochondrial cristae in the myocardium of adult was higher than that in aged (p < 0.05). The density of mitochondria in the myocardium of adult was higher than that in aged (p < 0.01). Compared with the adult Tibetan sheep, the mitochondrial crista of aged were relatively sparse, the crista membrane was wide, and the mitochondria were not closely linked, showing fragmentation. These results suggest that the myocardial mitochondria of the adult have better energy supply ability, indicating that aging can lead to the weakening of oxygen supply in the myocardial mitochondria of Tibetan sheep.