【Animal Modeling】-Comparison of the effects of restraint and isoflurane anesthesia on the HPA axis of heart rate variability in rats

  Objective: To observe the changes of heart rate variability in rats under restraint fixation and isoflurane (flow: 0.8L, concentration: 1.5%) anesthesia; and compare the effects of restraint intervention and isoflurane anesthesia on rats by 30min per day for 9 days. To evaluate the effect of long-term use of isoflurane anesthesia and restraint immobilization on the stress level of rats, select a more appropriate immobilization method for rats, and provide experimental methods for basic medicine. Important reference.

  METHODS: SD rats were randomly divided into 3 groups: blank group, restraint group, and isoflurane anesthesia group. In the acute experiment, the electrocardiogram of rats was recorded for 15 minutes, and the heart rate and heart rate variability of rats under restraint fixation and isoflurane anesthesia were observed. Changes. In the chronic experiment, the body weight, pain threshold changes, and hormone levels related to stress state were compared in the three groups before and after continuous intervention for 9 days (30 min/d).

  Results: 1) Acute test: Compared with the blank group, both the restraint intervention and isoflurane anesthesia caused the rat heart rate to increase significantly (P<0.01). Compared with the isoflurane anesthesia group, restraint The heart rate of rats in the control group increased more significantly (P<0.05). Compared with the rats in the blank group and the restraint group, the time-domain index SDRR and frequency-domain index HF of isoflurane anesthetized rats were decreased (P<0.05). 0.01; P<0.05), the LF value and LF/HF value of heart rate variability frequency domain indicators were increased (P<0.05, P<0.01). 2) Chronic experiment: compared with the blank group, the long-term restraint and The weight gain of the rats in the isoflurane anesthesia intervention decreased (P<0.05). Compared with the isoflurane anesthesia group, the weight gain of the restraint group was reduced more significantly (P<0.05). Compared with the blank group and the isoflurane group Compared with the rats in the alkane anesthesia group, the pain threshold of the rats in the restraint group decreased (P<0.05); there was no statistically significant difference between the rats in the blank group and the rats in the isoflurane anesthesia group. Compared with the rats in the anesthesia group, the levels of corticotropin releasing hormone (CRH) in the hypothalamus and the corticosterone (CORT) in the adrenal glands of the rats in the restraint group were decreased (P<0.05), while="" the="" content="" of="" serum="" crh="" was="" significantly="" higher="" than="" that="" rats="" in="" anesthesia="" group.="" there="" no="" significant="" change="" cort="" p="">0.05).

  Conclusion: The above results suggest that low concentrations of isoflurane can increase the heart rate of rats under anesthesia, reduce heart rate variability, and produce changes in the functional state of the autonomic nervous system dominated by sympathetic excitation. Produces the effects of chronic stress. In experiments that require immobilization of animals for a long time, isoflurane anesthesia is a better immobilization method than restraint immobilization.