Platelet response to laser-induced microvascular injury in the rabbit mesentery and the rabbit ear chamber. A statistical comparison

Abstract

Laser-induced microvascular injury combined with rabbit ear chamber techniques offers a satisfactory means of measuring platelet reactivity over extended periods in conscious animals. A factor limiting the general applicability of the technique may be difficulty in producing suitable ear chamber preparations. Since the rabbit mesentery can be quickly and easily prepared for microcirculatory studies we have evaluated this preparation as an alternative to the ear chamber for quantitative studies of platelet aggregation in vivo. Platelet activity at sites of laser injury in mesenteric microvessels was about half that observed in the ear chamber but the standard deviation of the observation was not similarly reduced. Despite this, it was possible to demonstrate significant suppression of platelet activity in both ear chamber and mesenteric preparations after dextran administration. In contrast, a significant increase in platelet reactivity could not be detected in animals previously subjected to a standardised laparotomy at sites of injury in mesenteric vessels while such an increase was consistently observed in ear chamber preparations. Thus, while the mesenteric model can be used in studies of inhibition of platelet reactivity at sites of laser injury it does not appear suitable for examination of situations of enhanced platelet reactivity in vivo.