| Part Ⅰ Identification of diagnostic biomarkers of disseminated intravascular coagulation induced by exertional heat stroke in a rat model Objective:Disseminated intravascular coagulation is a common,fatal complication in patients with exertional heat stroke.Early diagnosis for DIC can improve the prognosis of heatstroke patients.The present study aimed to identify simpler,more rapid biomarkers for diagnosis of DIC.Methods:Temperature monitors were implanted into the abdominal cavity of Sprague-Dawley rats,which were run on a treadmill at a temperature of 40 ℃ and relative humidity of 70% until their core temperature reached 40,41,42 or 43 ℃.Then blood samples were taken and analyzed for coagulation parameters and tissue samples were for histopathology,which were compared among the different temperature groups.Results:Severity of coagulation dysfunction,which was diagnosed based on the extent of histological microthrombosis,increased with core temperature.Logistic regression analysis associated DIC with higher core temperature,longer activated partial thromboplastin time and lower platelet count.Together,these three parameters identified DIC in the animals with sensitivity of 70.6%,specificity of 90.9%,positive predictive value of 9.1%,negative predictive value of 29.4%,and an area under the receiver operating characteristic curve of 0.887.Conclusions:These results in a rat model of DIC suggest that core temperature over 40 ℃,prolonged APTT and decreased platelet count may allow reliable,timely diagnosis of the complication,which should be examined in clinical trials.Part Ⅱ Characteristics of coagulation dysfunction in rats with exertional heatstroke at different core temperaturesObjective:To investigate the status of coagulation function in rats with exertional heatstroke at different core temperatures.Methods : Twenty-five SPF rats were implanted with remote sensing temperature capsule to monitor their core temperature.One week after the operation,the rats were randomly divided into control group(n= 5)and model group[40℃ group(n=5),41℃ group(n=5),42℃ group(n=5)and 43℃ group(n=5)].The rats in model group were used to establish model of exertional heatstroke byrunning at a temperature of 40℃ and relative humidity of 70%,and their core temperature were monitored by remote sensing temperature capsule.When the core temperature reached the predetermined temperature,the running time and distance were recorded.Coagulation assays were performed when the core temperature of model group reached the standard.Coagulation items were analyzed statistically including prothrombin time,activated partial thromboplastin time,platelet count,fibrinogen,thrombin time,thrombomodulin,and thrombin-sensitive protein-1,vonwillebrand factor,plasminogen activator inhibitor-1 and lactic acid levels.The above indexes of the control group were detected before the experiment of the model group.Results:Compared with the control group,the platelet count in the 40℃ group began to decrease significantly,and decreased with the increase of core temperature(P<0.05).Compared with the control group,PT and APTT in 41℃ group began to be significantly prolonged with the rising core temperature(P<0.05).Compared with the control group,40℃ group and 41℃ group,TT in the 43℃group was significantly prolonged(P <0.05).The levels of fibrinogen in the 40℃ group and 41℃ group were significantly higher than those in the control group(P<0.05).Compared with the control group,the level of v WF in the 40℃ group began to increased significantly with the rising core temperature(P<0.05).Compared with the control group,the level of TSP-1 in the 41℃ group was significantly increased,and gradually increased with the rising core temperature(P <0.05).Compared with the control group,the levels of TM and blood lactic acid in 42℃ group were significantly increased,and gradually increased with the rising core temperature(P<0.05).Compared with the control group,the level of PAI-1 in the 43℃ group was significantly increased(P<0.05).Conclusion:Exertional heatstroke rats shows endothelial cell injury and decreased platelet count when the core temperature reaches40℃,prolonged coagulation time when the core temperature reaches 41℃,and significant microcirculation disorder when the core temperature reaches 42℃.Part Ⅲ Preventive effect of Shengmaiyin on exertional heatstroke induced coagulopathy in ratsObjective : To explore the preventive effect of Shengmaiyin on coagulation dysfunction of exertional heatstroke.Methods :Fifteen SPF male SPF SD rats were randomly divided into sham operation group,heatstroke group and Shengmaiyin group(5 each group)after implantation of telemetry temperature capsule for 1 week.Rats in Shengmaiyin group were given with Shengmaiyin 0.02 ml/(g·d)by gavage for 5 days.The rats in heatstroke group and Shengmaiyin group ran in the artificial climate chamber(40 ℃,70%).The running time and distance were recorded when the core temperature reached 42 ℃.Blood samples were taken to detect prothrombin time,activated partial thromboplastin time,platelet count,blood lactic acid,thrombomodulin,thrombin sensitive protein-1,von Willebrand factor and plasminogen activator inhibitor-1.The pathological changes were observed in liver,kidney,lung,intestine and heart.Results: When the core temperature reached 42 ℃,the exercise distance and exercise time of rats in Shengmaiyin group were significantly longer than those in heatstroke group[(456.3±92.3)m vs.(282.8±87.5)m,P<0.05;(36.3±6.3)min vs.(21.7±7.0)min,P<0.05].Compared with the control group,PT and APTT in the heatstroke group were significantly prolonged[(13.8±0.7)s vs.(9.9±0.7)s,P<0.05;78.3(36.0,120.0)s vs.1 9.0(1 6.6,2 2.5)s,P < 0.0 5 ],L a c w a s s i g n i f i c a n t l y i n c r e a s e d [(10.5±2.0)mmol/L vs.(4.0±0.7)mmol/L,P<0.05],and PLT was s i g n i f i c a n t l y d e c r e a s e d [(5 9 0.3 ± 8 0.2)× 1 09/ L v s.(1750.3±283.0)×109/L,P<0.05],plasma TM,v WF,TSP-1 and PAI-1 levels were significantly increased [(2.2±0.5)ng/ml vs.(1.6±0.1)ng/ml,P<0.05;(953.1±60.0)pg/ml vs.(462.3±37.0)pg/ml,P<0.05;(78.1±19.8)n g / m l vs.(54.5±7.2)ng/ml,P <0.05;(1945.7±74.5)ng/ml v s.(1589.3±247.5)ng/ml,P<0.05].Compared with the rats in the heatstroke group,the APTT of the rats in the Shengmaiyin group was significantly shortened [36.6(31.1,46.1)s vs.78.3(36.0,120.0)s,P<0.05],and the PLT was significantly increased [(980.5±302.4)×109/L vs.(590.3±80.2)×109/L,P<0.05],plasma TM,v WF and PAI-1 levels were significantlyreduced[(1.9±0.1)ng/mlvs.(2.2±0.5)ng/ml,P<0.05;(701.6±32.0)pg/mlvs.(953.1±60.0)pg/ml,P<0.05;(1702.3±218.6)ng/ml vs.(1945.7±74.5)ng/ml,P<0.05].Thrombosis was found in the liver,kidney,lung,intestine and heart of rats in the heat stroke group,while no o b v i o u s t h r o m b o s i s w a s f o u n d i n t h e S h e n g m a i y i n g r o u p.Conclusion :Shengmaiyin can relieve vascular endothelial cells injury,reduce consumption of coagulation factors and platelets,and prevent coagulation dysfunction in rats with EHS. |
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