REGULARITIES OF THE DEVELOPMENT OF THE MITOCHONDRIAL APPARATUS AND EXTERNAL MITOCHONDRIAL MEMBRANES IN THE 2nd CMC COMPLEX (LV+ISH) OF WISTAR RATS

Abstract

Within 45 days in the 2nd-CMC there is a continuous increase in the absolute (Vma), relative (Vvma) MA volumes, the total surface area ƩSnmm and the average volume of one MX (∆Vmt). The graphs of the growth of Vma, ƩSnmm and ∆Vmt values have the form of an S-like curve, which indicates the presence of three consecutive periods of monotonic development of MA and its components. In the process of postnatal morphogenesis of MA in the 2n-CMC, the biological law “division ↔ fusion” is realized. The essence of the law is that the ontogenetic regulation of the MT number in the 2n-CMC is carried out by two biological mechanisms: the division of MT, which leads to an increase in the number of organelles in the CMC, and the fusion of MT, as a result of which the number of organelles decreases, but the volume of each MT increases. The expediency of “fusion ↔ division” of MC in the process of ontogenesis of CMC is as follows. During division, the number of MT increases and, at the same time, the number of copies of mt-DNA in 2n-CMC increases. Intensive division of MC occurs in the time interval (n / p -15) days. When MT fusion occurs, duplication of mt-DNA copies occurs in each MT, which was formed after the fusion of two previous organelles. The doubled content of mx-DNA in MT 2n-CMC correlates with an increase in the number of cristae in these organelles and the area of NMM. The fusion of MT is observed in the time interval (15-30) days. This is a period of intensive growth of MA 2n-CMC, which coincides with the third period of doubling the body weight of white rats and the activation of their motor activity.

Keywords

• postnatal cardiomyogenesis of the 2n-cmc
• mitochondrial apparatus
• mitochondrial division and fusion.