外源性IL-6促进IL-6基因敲除小鼠移植肝再生的研究

Exogenous interleukin-6 enhances the process of liver regeneration after liver transplantation in interleukin-6 knockout mice

目的观察外源性重组白细胞介素6（rIL-6）对白细胞介素6（IL-6）基因敲除小鼠原位肝移植后存活时间和移植肝再生过程的影响。方法动物为C57BL／6野生型小鼠和IL-6基因敲除小鼠，分为4组进行实验：基因敲除对照组，肝移植供、受者均为IL-6基因敲除小鼠；野生型对照组，以IL-6基因敲除小鼠为供者，野生型C57BL／6小鼠为受者；基因敲除rIL-6组，供、受者均为IL-6基因敲除小鼠，肝移植前1h于受者皮下注射rIL-6，1rr培／kg；野生型rIL-6组，以IL-6基因敲除小鼠为供者，野生型西7BL／6小鼠为受者，受者应用rIL-6，用法和用量同前组。观察受鼠的存活情况。获取移植肝，进行组织学和免疫组织化学检查。结果供肝冷缺血时间约为50min。基因敲除对照组受鼠平均存活2．2d，野生型对照组受鼠平均存活1：9d，基因敲除rIL-6组受鼠平均存活〉17．6d，野生型rIL-6组受鼠平均存活〉20．4d。各组间存活时间的差异均有统计学意义（P〈0．01）。基因敲除对照组和野生型对照组受鼠移植肝有片状坏死和肝细胞气球样变，有极少数溴脱氧尿核苷染色阳性的细胞存在。基因敲除rIL-6组和野生型rIL-6组受鼠的移植肝无细胞坏死等改变，有散在的肝细胞溴脱氧尿核苷染色阳性。结论外源性的IL-6能够延长IL-6基因敲除小鼠肝移植后的存活时间，促进其移植肝细胞再生。

Objective To observe the effects of exogenous interleukin （IL）-6 on survival time and regeneration of liver grafts in an orthotopic liver transplantation model in IL-6 knockout （KO） mice. Methods A model of liver transplantation in C57BL/6 wild type （WT） and IL-6 KO mice with C57BL/6 background was established. Grafts were preserved at 4 ℃ in UW solution before transplantation. Study was divided into 4 groups： IL-6 KO→IL-6 KO control group, IL-6 KO→C57BL/6 WT group, IL-6 KO→IL-6 KO＋ rlL-6 group, and IL-6 KO→C57BL/6 WT＋ rIL-6 group. Recipient animals were injected subcutaneously with human recombinant IL-6 （1 mg/kg body weight） 1 h before transplantation. Survival of liver grafts after transplantation was followed up. Hepatocyte replication with BrdU uptake after liver transplantation was examined by immunohistochemistry. Results A total of 48 liver transplantations were performed. Cold ischemic time was 50 min. The survival time of liver grafts in the control group was 2. 2 days, and that was 1.9 days, 〉17. 6 days and 〉20. 4 days in IL-6 KO→C57BL/6 WT group, IL-6 KO＋ rIL-6 group and C57BL/6 WT＋ rIL-6 group respectively with the the difference being statistically significant among the latter three groups （P〈0. 01）. The liver grafts transplanted in control group recipients showed patchy areas of necrosis and hepatocyte ballooning. Slight increase in BrdU uptake was found at 48 h post-transplantation. Minimal injury and no necrosis were observed in IL-6 treated groups. Mild increase of BrdU uptake was demonstrated at 48 h after liver transplantation. Conclusion Exogenous recombinant IL-6 appears to significantly prolong the survival time of IL-6 KO liver grafts after liver transplantation and enhance the regenerative response after liver transplantation in IL-6 NO mice.