| Objective: To observe whether the rats with hemorrhagic shock have sensitive effect on angiotensin(Ang)?hypertensive response.Methods:Animal source and feeding: Twenty Sprague-Dawley(SD)male rats of 10-12 weeks old,with a body weight of 250±10g,were purchased from Beijing fangyuanyuan farm.The male rats in this study were raised in isolation environment.The living environment temperature of the animals was 24±2,the relative humidity of the living environment was 40%-80%.Animals were fed with standard rat chow and water.Rat chow was also purchased from Beijing fangyuanyuan farm.Twenty male rats were used in our experiment and fed adaptively for one week before the experiment.Experimental groups: according to the random principle,the experiment was divided into 2 groups,10 rats in sham hemorrhage group(Sham group)and 10 rats in hemorrhage group(Hemo group).Experimental operation: A: Installation of telemetric probes through femoral artery(HD-S10,DSI)was conducted: rats in sham and hemorrhagic groups were implanted with probes(HD-S10,DSI)through femoral artery under pentobarbital anesthesia,followed by one week recovery.Then,the computer automatic acquisition program to record 5 minutes per hour was set up,and recording of basic parameters including mean arterial pressure,systolic blood pressure,diastolic pressure,heart rate,temperature and animal activity for 5 days was started.B: Femoral artery intubation,blood loss and retransmission: after recording baseline blood pressure and heart rate five days,the femoral artery was intubated and the rats were bled through the femoral artery(1.5ml per minute,5ml in total for each rat)for two times and bleeding time is 1 day apart.The blood pressure was reduced to 40 mmh Hg by bleeding and maintained for 30 minutes.The blood was collected with heparin tube and centrifuged,the upper serum was poured out,and the blood cells were resuspended in the saline solution by adding the same amount of normal saline and were reinfused into the rats.Femoral artery intubation without bleeding in sham bleeding group.C: Implantation of Ang?osmotic pump: After the second bleeding one week,according to the body weight of the animal,we prepared an Ang?(120ng / kg / min)and put it into a osmotic pump(osmotic pump,model 2002,Alzet)which can release for two weeks,and then implanted it under the skin of the back of the rat.The changes of blood pressure in all animals were recorded continuously for 14 days by the DSI system.The changes in blood pressure and heart rate variability were analyzed.Comparative observation of the effect of controlled hemorrhagic shock on the rise of hypertension induced by Ang?in rats.Results:1.Before administration of Ang?,there was no significant difference in the mean arterial pressure between the hemorrhage group of rats(105.2±2.4mm Hg)and the sham hemorrhage group of rats(109±4.1mm Hg);2.After administration of Ang ?for two weeks,the mean arterial pressure change in the hemorrhage group of rats(50.8±2.9mm Hg)was higher than that in the sham hemorrhage group of rats(30.3 ± 0.6mm Hg)(P< 0.05);3.Before administration of Ang ?,there was no significant difference in the mean heart rate between the hemorrhage group of rats(358.7±10.2beats/min)and the sham hemorrhage group of rats(349.1±6.2beats/min);4.After administration of Ang ?for two weeks,there was no significant difference in the mean heart rate between the sham hemorrhage group(-11±7.6beats/min)and the hemorrhage group(-8.1±8.1beats/min)(P >0.05).Conclusions:Male rats with hemorrhagic shock stress increased hypertensive response to Ang? when compared to the sham hemorrhage group of rats,while there was no significant effect on the sensitivity of Ang?administration to increase heart rate in male rats. |
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