Stability of bovine platelets stored at ambient temperature

The functional and ultrastructural stability of bovine platelets, stored in homologous plasma at 22 °C for periods up to 96 h, were examined. In only approximately 22% of the platelets stored for the full period was there any evidence of moderate ultrastructural alterations compared to the freshly prepared samples. The most obvious morphological changes in the stored platelets included an increase in the number of dense granules in contact with the platelet membrane and an increased heterogeneity in the appearance of the alpha granules. The microtubules of the circumferential band remained intact and there was minimal evidence of activation of the bovine platelets due to storage. The functional response to ADP, platelet activating factor (PAF) or collagen was maintained for the first 48 h of storage. The aggregation response to ADP was 81.3% of the initial value after 96 h of storage whereas the response to PAF was 86.2% and 54.7% of the initial value at 72 and 96 h respectively. Although the collagen aggregation response also declined to 54.8% of the initial value by 96 h, the release of thromboxane in response to collagen stimulation was similar in the stored and fresh samples.