A Study of Age-Dependent Changes of Mitochondria in Sceletal Muscles and Heart of Naked Mole Rat (Heterocephalus glaber)
Morphometric evaluation of mitochondria in skeletal muscle and heart of naked mole rat (Heterocephalus glaber) at the age of 6 and 60 months has been carried out. The experiments revealed a significant increase of the total area for cross-sections of mitochondria of muscle fibers with age. As six month age, the ratio of the mitochondrial area to total area of muscle fibers for mole rat was 4.8 ± 0.4%. With age, this value rises to 12.7 ± 1,8%. The number of mitochondria - the number of mitochondria in the cross sections of 1 mm<sup>2</sup> muscle fiber increased with age from 0.23 ± 0.02 units to 0.47 ± 0.03. As to the average cross-sectional area of one mitochondria in skeletal muscle, it increased from 0.21 ± 0.01 mm<sup>2</sup> to 0.29 ± 0.03 mm<sup>2</sup>. Thus, with the age, skeletal muscle of mole rat comes to multiple increase of mitochondrial apparatus by increasing the numbers of mitochondria, and their size, shaping neotenic chondriom type. Such a change was found to be accompanied by retention in adult mole rats some traits of mitochondrial and oxidative phosphorylation and lowered level of matrix adenine nucleotides, typical for embryos and neonates of short-lived rodents (rats and mice).