الفهرس 
Introduction and Aim of the WorkOnly 14 pages are availabe for public view
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Abstract
Myocardial infarction (MI) is a major public health problem and the
leading cause of mortality in both developed and developing countries. Cell
transplantation is considered as a promising therapeutic approach for MI
This work aims at investigating the role of stem cells from the umbilical
cord blood in treatment of myocardial infarction.
Materials and Methods: Fourty male albino rats were used in this study.
They were divided into three groups; the first served as control, the second
and third groups were injected by isoproterenol daily for two days to induce
myocardial infarction and 10 days after induction of MI the rats in the third
group were injected with 500.000 stem cells suspended in 0.5 ml phosphate
buffer saline in caudal vein. Then, the rats were sacrificed after thirty days
from stem cells injection. The heart specimens were processed for light
microscopic examination using H&E , Prussian blue, Masson’s trichrome
stains, in addition to immunohistochemistry technique using CD34 and
troponin T antibodies.
Results: In MI group, there were destroyed, interrupted, separated, wavy
and darkly eosinophilic cardiac muscle fibers with no cross striations or
nuclei in many fibers, ghost and enlarged rectangular nuclei in other
fibers, multiple vacuoles and contraction band necrosis also appeared.
Vacuolated areas, dilated congested blood vessels, extravasted red blood
corpscules (RBCs) and cellular infiltration were present inbetween cardiac
muscle fibers. This destruction confirmed by a significant decrease in
troponinT area% when compared to control group. There was collagen
I
deposition inbetween cardiac muscle fibers and subendocardium confirmed
by a significant increase in mean collagen area % when compared to control
In MI and stem cells group, collagen deposition decreased inbetween cardiac
muscle fibers and subendocardium as confirmed also by morphometric and
statistical analysis. There was increased neovascularisation detected by
CD34 immunostain positive-endothelial cells lining many small blood
vessels and confirmed by significant increase in CD34 area % when
compared to MI groups. The cardiac muscle fibers appeared healthy with
normal arrangement and little interstitial spaces confirmed by a significant
increase in the healthy cardiac muscle expressed by troponinT area% when
compared to MI group.
Conclusion and recommendations: The mesenchymal stem cells
extracted from umbilical cord blood have a potential role in the treatment of
myocardial infarction through decreasing fibrosis and increasing
neovascularization in and around the infarcted area which improve tissue
perfusion , decrease apoptosis of hypertrophied myocytes, maintain
survival of viable myocardium, reduce collagen deposition and improve
cardiac function . Further researches are recommended to study the role of
cord blood mesenchymal stem cells in treatment of MI infarction or other
cardiac diseases in human.
Key words: isoproterenol, myocardial