Establishment of long-term survival rat model of moderate to severe sepsis

  OBJECTIVE: To establish a long-term survival rat model of moderate to severe sepsis, observe the natural progression of sepsis, and provide new ideas and methods for the study of sepsis. Methods: Forty SD rats were divided into a control group (sham group, 8) and a cecal ligation and puncture group (CLP group, 32). All operations were performed in a small animal anesthesia machine, sevoflurane It is done under inhalation anesthesia. All rats established arteriovenous access in their right neck. After 24 hours of recovery, rats in the CLP group had sepsis through cecal ligation and perforation. After the operation, the rats were transferred to the recovery room (indoor temperature 22~25℃) and kept in a single cage. After the operation, intravenous rehydration was given with 6% HEAS and 5% glucose injection in a ratio of 1:1, and the rehydration amount was 20 mL/kg/12 h on the first and second days. After that, the fluid was halved until the rats started eating. According to the survival of the rats, the rats in the CLP group were naturally divided into survival group (survival group) and death group (dead group). Observe the rats up to 30 days after operation, record the symptoms, body weight changes, and plasma concentration of IL-10, and observe the changes in abdominal organs by dissection.

   Results: (1) In the CLP group, the survival rate was 75% within 24 hours, 62.5% within 72 hours, and 50% within 7 days. (2) According to the sepsis severity assessment system, 32 rats in the CLP group reached moderate to severe sepsis 24 hours after surgery. (3) After the operation, the weight of survival group and sham group decreased. The rats in the survival group dropped significantly from day 4 (P=0.017). The survival group had the lowest weight on the 6th day after surgery, which was (8.51±2.23)% lower than the original weight; the sham group had the lowest weight on the 4th day after the operation, which was (2.73±1.82)% lower than the original weight. The group difference was statistically significant (P=0.026). On the 30th day after surgery, there was no significant difference in the maximum increase rate of body weight between the two groups of rats (sham group (16.16±2.39)% and survival group (13.03±3.74)% (P=0.29)). (4) Compared with the preoperative (0 d) day, the plasma concentration of IL-10 in the three groups all increased, the survival group (P=0.000) and the dead group increased significantly (P=0.010). (5) For abdominal anatomy: In the dead group, a large amount of foul-smelling ascites, ligation of the intestine was purple and black, no wrapping, no adhesion. In the survival group, the abdominal cavity was extensively adhered, and the greater omentum lost its original shape and luster, tending to ligate the intestine, but no abscess. The spleen of the survival group accounted for (2.64±0.37)‰ of the body weight, and the ratio of the spleen of the sham group to (1.63±0.20)‰, the difference was statistically significant (P=0.032).

   Conclusion: This experiment provides reliable measures to control CLP and a method to screen models for the establishment of a CLP model for long-term survivors of moderate to severe sepsis, so that it basically conforms to the law of occurrence and development of sepsis.