Закономерности кинетики роста массы сердца, комплекса (лж + мжп) и паренхимы миокарда в пренатальном и постнатальном онтогенезе крыс

Abstract

Проведено органометричне дослідження зростання маси серця, комплекса (лівий шлуночок + міжшлуночкова перетинка) і паренхіми міокарда ЛШ до та в ранні терміни після народження щурів лінії Вістар. Встановлено, що на протязі 45 діб постнатального життя щурят маса серця збільшується в 12 разів, від 30 ± 5 мг до 360 ± 20 мг, маса (лж+мжп) збільшується у 24 рази від 11,5 ± 2 мг до 279,4 ± 25 мг і маса паренхіми міокарда в (лж+мжп) зростає в 25 разів, від 8,9 ± 2 мг до 223,5 ± 20 мг.

Проведено органометрическое исследование роста массы сердца, комплекса (левый желудочек + межжелудочковая перегородка) и паренхимы миокарда до и после рождения крыс. Установлено, что за 45 суток постнатальной жизни крысят масса сердца увеличивается в 12 раз, от 30 ± 5 мг до 360 ± 20 мг, масса комплекса (лж+мжп) возрастает в 24 раза от 11,5 ± 2 мг до 279,4 ± 25 мг и масса паренхимы миокарда в комплексе (лж+мжп) возрастает в 25 раз, от 8,9 ± 2 мг до 223,5 ± 20 мг.

Wistar rats were used: 15-16 and 20-21 diurnal embryos, newborns, 5, 10, 15, 20, 25, 30, 35, 40, 45 day-old rats. Only 12 age groups. In each age group there were 5-10 individuals, mostly from the same litter. For further work, rats with body weight not exceeding 10-15% of the mean value for a group of animals were selected. After anesthesia in the rats, the heart was removed, which was placed in a filter on the ice to stop the heartbeat. The vessels were cut off, the chambers of the heart were released from blood clots. Isolated hearts were weighed (mсor, mg). Then, the atria were removed and the mass of the left ventricular wall was determined with an interventricular septum (ml, mg). From slices of LV of rats of different age half-thin sections were prepared. With microscopy of stained sections (1000x), the volume fraction (relative volume) of myocardial parenchyma (Vvpar, %) was determined using an ocular mesh (No = 225). It is established that the growth mass of the heart mcor = f1 (t) of the rat before and after birth has the form of an elongated letter “S”. For 45 days postnatal development of the rat, the heart mass increased 12 times, from 30 ± 5 mg to 360 ± 20 mg. The graph of the kinetics of the growth of the LV mass mlzh = f2 (t) also has the form of an elongated letter “S”. For 45 days of postnatal development of rats, the absolute mass of LV increased monotonically 24 times from 11.5 ± 2 mg (newborns) to 279.4 ± 25 mg, and the relative mass of the left ventricle increased by 2 times, from 38.5% to 77.6 %. Morphometric indices mL and Vvpar were used to determine the growth kinetics of the absolute mass of the myocardial parenchyma mpar = f3 (t) in the left ventricle of the rat heart of different ages. Calculations were carried out according to the formula: mpar = mł x Vvpar. It was found that for 45 days of postnatal development of rats, the mass of myocardial parenchyma in the LV increased monotonically 25 times, from 8.9 ± 2 mg to 223.5 ± 20 mg. Consequently, in the early periods of ontogeny of Wistar rats, monotonous growth of the mass of the heart, left ventricle and parenchyma of the myocardium of the LV is observed.