ACTIVATION OF MAST CELLS AFTER EXPERIMENTAL MYOCARDIAL INFARCTION IN 3 WEEK-OLD RATS
I. L. Erokhina,1 M. G. Martynova,1 O. M. Moiseeva,2
O. I. Emelyanova 1
1 Institute of Cytology RAS, St. Petersburg, and 2 V. A. Almazov Institute of
Cardiology, St. Petersburg;
1 e-mail: heartdev@mail.cytspb.rssi.ru
It is known that mast cells (MC) take an active part in regeneration processes in postinfarction heart in adult
rats and humans. Behaviour of population of cardial MCs has been studied 20, 60, 75 and 90 days after experimental
myocardial infraction induced in 3 week-old and adult rats by ligation of left coronary artery. The density of MC of
different degrees of maturity was estimated in atrium and ventricle on paraffin sections stained with Alcian blue -
Safranin. Findings were compared with MC density obtained in hearts of intact rats. The MC density in intact 1.5-2.5
month-old rats in atrium and ventricle was about 0.6 cells/mm2, in intact 3.5-4.0 month-old rats in
atrium - 1.2 cells/mm2, in ventricle - 0.6 cells/mm2. The MC density in 3 week-old rats with
infarction was significantly higher than in intact rats: 5-fold increase in 20 and 60 days in atrium, and 2-fold
increase in 60 and 75 days in ventricle. In 60 days after infarction the MC density in adult rats was 3 times lower
in atrium and 2 times lower in ventricle than in the same heart compartments of 3 week-old rats with infarction.
After infarction in 3 week-old rats, a relative share of young cells with alcian-positive granules sharply increased
in 20 days and then decreased by 60-75 days. This indicates a migration of immature MCs to infracted myocardium and
their subsequent differentiation. The MC activation after infraction in young rats may result from a more active
immune reaction in younger rats and/or functional peculiarities of their MC.
Key words: mast cells, heart, myocardial infarction, rats, postnatal development
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