Effect of Cardiovascular Injury on Catabolism of Adenosine and Adenosine 5-‘Triphosphate in Systemic Blood in a Freely Moving Rat Model In Vivo

Background: Previous studies have shown that catabolism of adenosine 5’-triphosphate (ATP) in red blood cell (RBC) may be a key factor for cardiovascular protection and maintaining cardiovascular homeostasis. Objective: To investigate the effect of cardiovascular injury on adenosine and ATP catabolism in systemic blood using a freely moving rat model in vivo. Method: After acclimatized to the experimental environment, Sprague Dawley (SD) rats were each given either isoproterenol (30 mg/kg) or saline (1 mL/kg) by subcutaneous (sc) injection. Blood samples were collected sequentially for up to 6 hours for measurement of red blood cell (RBC) concentrations of adenine nucleotides and plasma concentrations of adenosine and its oxypurine metabolites. Results: We have found isoproterenol induced 50% mortality under the experimental condition. Plasma concentrations of adenosine (ADO) and uric acid (UA) and red blood cell (RBC) concentrations of adenosine 5’-diphosphate (ADP) and adenosine 5’-monophosphate (AMP) in RBC were significantly higher in the isoproterenol treated rats (p < 0.05 for all the comparison). On the other hand, plasma concentrations of hypoxanthine (HYP) were higher in the control group (p < 0.05), but there was no statistically significant changes in ATP concentrations in the RBC (p > 0.05). Conclusion: Cardiovascular injury induced by isoproterenol resulted in breakdown of ATP to ADP and AMP in the RBC and also breakdown of ADO to UA in plasma and other tissues.