[Improvement of method to produce septic shock model of rats]

To investigate the feasibility of method improved for developing septic shock rats model.

Studies were performed on 60 adult male Sprague-Dawley rats. They were randomized into sham group and standard CLP (J Group) group (n = 20), A (n = 10), B (n = 10), C (n = 10) group and J group was further to two subgroups (n = 10) J1 and J2 group. The ligated distance of A, B and C group were 20%, 30%, 50% of the cecum respectively. Standard CLP procedures were made in J group as described previously. Sham group just sham operated. MAP was monitored continuously in A, B, C and J1 groups for 5h, and the MAP dropped to 70% of the baseline was defined as septic shock, MAP was monitored for more than 10 hours until it reached 70% of baseline or lower in the J2 group. The white blood cell count, endotoxin and histopathological changes in lung and renal tissue were observed in each groups.

At 5h after operation, there is no change of MAP in sham, J1, A and B groups, but it dropped to 70% of the baseline [(73 ± 10) mmHg] in C group. Compared with sham group, the level of endotoxin [(17 ± 5) vs (456 ± 28) vs (596 ± 29) vs (982 ± 11) vs (209 ± 40) pg/ml] and white cell count [(6.3 ± 3.7) vs (4.6 ± 1.4) vs (3.7 ± 1.2) vs (3.3 ± 2.6) vs (4.2 ± 1.2)×10(9)/L] was significantly higher and lower respectively in A, B, C and J1 groups. Obvious pulmonary and nephridia tissue edema, inflammatory cell infiltration was observed in C group, but the inflammatory cell infiltration was not found in A, B and J1 groups, The manifestations of J2 group rats is similar with C group.

The rat model produced by ligating 50% cecum can reproduce the pathophysiology of septic shock, and the time needed to prepare septic shock was significantly shorter. The improved model has application value for septic shock study.