Abstract:
For many years acetylsalicylic acid (ASA) has been used as an analgesic, antiinflammator and antipyretic agent. In the past decade, the use of ASA has increased because it is thought to be beneficial for the cardiovascular system. Acetylsalicylic acid has been shown to reduce the risk of death from cardiovascular-related disorders such as myocardial infarction, unstable angina, and stroke. The purpose of this study was to determine the effects of ASA on blood viscosity in healthy rats, Rattus norvegicus. The effects of ASA were investigated at different concentrations (40 and 80 mg/kg body weight (bw) per day for one week) and for different time intervals (40 mg/kg bw ASA/day for one week, one month and two months, respectively). At the end of the experiment, the apparent viscosity o t he plasma and of three different hematocrits was measured with a Wells-Brookfield cone-plate viscometer at ten different shear rates. In addition, protein concentration was determined for the plasma of each rat. The data suggest that as the hematocrit increased from 30% to 45%, the viscosity of the group which received 40 mg/kg bw ASAJday for one week was significantly higher than all other groups, particularly as shear rate increased. No significant differences were observed in any of the other experimental groups when compared to the control group. This study suggests that the effects of acetylsalicylic acid on blood viscosity are dose and time dependent. It is possible that doses higher than 40 mg/kg bw or ASA treatment longer than one week trigger an adaptive response which is initiated upon an initial increase in blood viscosity. As a result, blood viscosity is unaltered.
