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Experimental study on microthrombi and myocardial injuries
Microvascular Research
|January 1, 1996
Summary
High molecular weight dextran induced microthrombi in rats, leading to myocardial injuries. These injuries, indicated by ECG changes, correlated with increased thromboxane B2 and reduced Na(+)-K(+)-ATPase activity.
Area of Science:
- Cardiovascular physiology
- Hematology
- Biochemistry
Background:
- High molecular weight dextran administration can induce changes in blood circulation.
- Microthrombi formation is a potential cause of tissue injury.
- Electrocardiogram (ECG) changes, such as S-T segment elevation, indicate myocardial injury.
Purpose of the Study:
- To investigate the effects of high molecular weight dextran on rat microcirculation and myocardial function.
- To determine the correlation between microthrombi formation, ECG abnormalities, and biochemical markers.
- To assess the impact of microthrombi on myocardial cell membrane Na(+)-K(+)-ATPase activity.
Main Methods:
- SD male rats were intravenously injected with high molecular weight dextran for 4 days.
- Microcirculation was observed using mesentery microscopy.
- ECGs were monitored to detect changes in the S-T segment.
- Blood samples were analyzed for platelet aggregation, plasma TXB2, and 6-K-PGF1 alpha levels.
- Na(+)-K(+)-ATPase activity in myocardial cell membranes was measured.
Main Results:
- Dextran injection led to the formation of microthrombi in venules and capillaries.
- Rats developed elevated S-T segments on ECG, indicative of myocardial injury.
- A significant positive correlation was observed between microthrombi count and S-T segment elevation (r = 0.944, P < 0.01).
- Platelet aggregation increased, accompanied by a decrease in platelet count.
- Plasma TXB2 levels increased significantly, correlating with S-T segment rise (r = 0.889, P < 0.05).
- Na(+)-K(+)-ATPase activity on myocardial cell membranes was significantly reduced (P < 0.01) and negatively correlated with S-T segment rise (P < 0.05).
Conclusions:
- High molecular weight dextran induces microthrombi formation and myocardial injury in rats.
- The observed myocardial injuries are closely linked to the extent of microthrombi and associated biochemical changes.
- Reduced Na(+)-K(+)-ATPase activity may contribute to the observed myocardial dysfunction.