RESUMEN
<p><b>OBJECTIVE</b>To explore the effect of temperature dropping process in cold air on the coagulation function both in healthy and hypertensive rats.</p><p><b>METHODS</b>Twenty-four male healthy Wistar rats and 24 male spontaneous hypertensive rats (SHR) were randomly divided into the minimum temperature group (Tim), Tmin control group (Tmin-c), recovery temperature group (Tr) and Tr control group (Tr-c), With the simulated temperature dropping process of a cold air, collected from Zhangye city in March of 2011, the groups of Tmin and Tr were exposed to this process. Both at the Tmin and Tr, blood were collected from the rats for coagulation function measurements.</p><p><b>RESULTS</b>Compared with the control group, no significant difference was found in the results of activated partial thrombin time(APIT), pro-thrombin time (PF) and thrombin time (TT) between any groups in any strains (P > 0.05). The fibrinogen (Fbg) and fibrinogen-time were found to be obvious higher and shorter in Tmin and Tr of healthy rats and in Tmin of hypertensive rats in contrast to the control group. Hypertensive rats had higher level of fibrinogen and shorter level of fibrinogen-time.</p><p><b>CONCLUSION</b>The temperature dropping process induced the increase of plasma Fbg both in the healthy and hypertensive subjects, which might be the reason to explain the higher occurrence of cardiovascular diseases event especially these activated through the formation of thrombin during cold air stress. Besides, the coagulation function of healthy subjects was more likely to be affected by cold air than the hypertensive subjects.</p>