两种脓毒症模型小鼠血清白细胞介素-6与其早期生存率的关系

Relationship between interleukin-6 and the early survival rate of mice in two septic models

目的探讨盲肠结扎穿孔（ CLP）、腹腔持续置管引流（ CASP）脓毒症模型小鼠血清白细胞介素-6（IL-6）与其早期生存率的关系。方法将60只雄性BALB/c小鼠编号,采用数字表法随机分为3组,即假手术组（ Sham组）、CLP组、CASP组,各20只。 CLP组小鼠麻醉后,于中下腹正中线做纵行切口,充分暴露并结扎盲肠,用18 G注射器针头在结扎部位远端穿孔并来回贯穿2次,将少量肠内容物挤出,回纳盲肠,缝合腹壁切口。 CASP组术前准备、开腹方式同CLP模型,暴露小鼠升结肠系膜,在其对侧处插入静脉导管,退出针芯,荷包缝合并固定、剪断静脉导管,将游离端放置于腹腔内。用棉签挤压肠管,使少量肠内容物从导管口溢出,以确认导管通畅。 Sham组术前准备、开腹、术后处理同CLP组,不行盲肠结扎、穿孔。观察各组小鼠术后12、24、36、48、60、72 h的生存率。术后6 h采集各组小鼠尾静脉血,采用 ELISA 检测血清 IL-6,比较此时间点3组存活小鼠间 IL-6水平以及CLP组、CASP组的存活和死亡小鼠间IL-6水平。结果 Sham组、CLP组和CASP组术后72 h生存率分别是100.0%（20/20）、45.0%（9/20）和10.0%（2/20）,3组间总体比较差异有统计学意义（字2=32.970,P〈0.01）,两两比较3组间差异均有统计学意义（P值均〈0.05）；3组小鼠生存时间曲线经Log-rank检验,差异有统计学意义（字2=34.030,P〈0.05）。术后6 h,Sham组、CLP组、CASP组存活小鼠血清 IL-6水平分别是（36.62依10.30） ng/L、（2443.47依970.50） ng/L、（4057.93依827.41）ng/L,差异均有统计学意义（Hc=29.270,P〈0.01）；CLP组和CASP组各组内存活小鼠血清IL-6水平平均分别为（1348.80依276.25） ng/L、2100.00 ng/L,明显低于死亡小鼠的（3157.29依330.94）ng/L、（4275.48依512.71）ng/L,CLP组差异有统计学意义（t=13.071,P〈0.01）。结论两种脓毒症模型小鼠的转归都有一定的病死率,较好地模拟了脓毒症的病理生理过程,CLP模型侧重于模拟局限性腹腔脓肿,CASP模型则侧重于模拟弥漫性腹膜炎。 CLP组模型术后6 h血清IL-6水平较低的小鼠,术后72 h生存率较高。

Objective To explore the relationship between the serum interleukin-6 （ IL-6 ） levels, cecal ligation, perforation（CLP） , colon ascendens stent peritonitisc（CASP） and the survival rate of mice during early stage. Methods Sixty male BALB/c mice were divided into three groups by using random digits table（20 mice in each group）, which were Sham group, CLP group and CASP group. In the CLP group, a midline laparotomy was performed and the cecum was fully exposed with adjoining intestine after complete anesthesia. The cecum was tightly ligated at its base and punctured twice by an 18 G needle. The cecum was then gently squeezed to extrude a small amount of stool from the perforation sites. CASP group was similar to the preoperation preparation and the ＂open＂ method of CLP group. After exposure of the ascending colon, the prepared catheter was stitched through the antimesenteric wall into the lumen of the ascending colon and was then fixed with two stitches. Consecutively, the inner needle of the stent was removed and the stent was cut as the prepared site. To ensure the proper intraluminal positioning of the stent, stool was milked from the cecum into the ascending colon and the stent until a small drop of stool＆nbsp;appeared. The survival rates of several time points after surgery were observed in each group. Six hours after the surgery, the ELISA was developed for detecting murine serum IL-6 in these three groups and the IL-6 levels of living and dead ones in both CLP and CASP group were compared. Results The 72 h survival rates of Sham, CLP and CASP group were 100. 0% （20/20）, 45. 0% （9/20） and 10. 0% （2/20） respectively , the differences was statistically significant （字2 =32. 970, P〈0. 01）. Compared in pairs, the differences between all three groups were significant （all P values 〈0. 05）. Differences in survival were assessed by using Log-rank test, and which had statistical difference （字2 =34. 030, P〈0. 05）. On the 6th hour postoperatively, the IL-6 levels of Sham group, CLP group and CASP group were （ 36. 62 ±10. 30）ng/L, （2 443. 47 ±970. 50） ng/L, （4 057. 93 ±827. 41） ng/L, respectively, with statistical significance （Hc = 29. 270, P 〈 0. 01）. The serum IL-6 levels, of the living mice[（1 348. 80 ±276. 25）ng/L, 2 100. 00 ng/L] were lower than the dead ones[（3 157. 29±330. 94）ng/L, （4 275. 48±512.71）ng/L], 6 h after the surgery, in both CLP and CASP group （tCLP = 13. 071, P 〈 0. 01）. Conclusions With certain mortalities, these two animal models closely mimic the clinical course of intra-abdominal sepsis. The CLP model mainly emphasizes to stimulate the local peritoneal abscess while the CASP model is similar to diffuse peritonitis. The group with lower serum IL-6 levels 6 h after surgery has higher survival rate 72 h after the operation.