摘要目的:探讨布鲁顿酪氨酸激酶（BTK）在内毒素/脂多糖（LPS）诱导烫伤小鼠肠道细胞焦亡中的作用。方法:采用实验研究方法。将128只6~8周龄的雄性C57BL/6小鼠分成假伤组、单纯烫伤组、烫伤+LPS组、烫伤+LPS+3 mg/kg LFM-A13组、烫伤+LPS+10 mg/kg LFM-A13组、烫伤+LPS+30 mg/kg LFM-A13组，假伤组8只，其余5组分别为24只。烫伤5组小鼠造成背部10%体表总面积Ⅲ度烫伤，假伤组小鼠背部模拟致伤。伤后0 h（即刻），假伤组、单纯烫伤组小鼠腹腔注射生理盐水，烫伤+LPS组小鼠腹腔注射LPS，其余3组小鼠腹腔注射LPS及相应剂量的LFM-A13。假伤组小鼠于伤后0 h处死，收集肠道组织和血清；烫伤5组分别于伤后0、12、24 h，每组取8只小鼠处死，收集肠道组织及伤后12 h血清。采用免疫组织化学法检测小鼠肠道组织BTK磷酸化情况。采用蛋白质印迹法检测小鼠肠道组织磷酸化BTK和剪切型胱天蛋白酶1（caspase-1）、caspase-11蛋白表达情况。采用酶联免疫吸附测定法检测小鼠肠道组织和血清白细胞介素1β（IL-1β）含量。对数据行单因素方差分析、LSD检验。结果:6组小鼠伤后0 h及单纯烫伤组小鼠伤后12、24 h肠道组织未见明显BTK磷酸化情况。伤后12、24 h，烫伤+LPS组小鼠肠道组织BTK磷酸化较单纯烫伤组明显增加，烫伤+LPS+3 mg/kg LFM-A13组、烫伤+LPS+10 mg/kg LFM-A13组、烫伤+LPS+30 mg/kg LFM-A13组小鼠肠道组织BTK磷酸化较烫伤+LPS组明显下降，且随着LFM-A13剂量的增加，下降程度逐渐增加。与假伤组（0.130±0.010）及单纯烫伤组（0.120±0.040、0.110±0.040）比较，烫伤+LPS组小鼠伤后12、24 h肠道组织磷酸化BTK蛋白表达明显升高（0.470±0.090、0.430±0.080， P<0.01）。与烫伤+LPS组比较，烫伤+LPS+3 mg/kg LFM-A13组小鼠伤后24 h及烫伤+LPS+10 mg/kg LFM-A13组、烫伤+LPS+30 mg/kg LFM-A13组小鼠伤后12、24 h肠道组织磷酸化BTK蛋白表达明显下降（0.280±0.060，0.300±0.120、0.150±0.050，0.280±0.090、0.140±0.040， P<0.05或 P<0.01）。与烫伤+LPS+3 mg/kg LFM-A13组比较，烫伤+LPS+10 mg/kg LFM-A13组、烫伤+LPS+30 mg/kg LFM-A13组小鼠伤后24 h肠道组织磷酸化BTK蛋白表达明显下降（ P<0.01）。与假伤组和单纯烫伤组比较，烫伤+LPS组小鼠伤后12、24 h肠道组织剪切型caspase-1、caspase-11蛋白表达明显增加（ P<0.01）。与烫伤+LPS组比较，烫伤+LPS+3 mg/kg LFM-A13组小鼠肠道组织伤后12 h剪切型caspase-1和伤后12、24 h剪切型caspase-11蛋白表达及烫伤+LPS+10 mg/kg LFM-A13组、烫伤+LPS+30 mg/kg LFM-A13组小鼠伤后12、24 h肠道组织剪切型caspase-1、caspase-11蛋白表达明显减少（ P<0.01）。与烫伤+LPS+3 mg/kg LFM-A13组比较，烫伤+LPS+10 mg/kg LFM-A13组、烫伤+LPS+30 mg/kg LFM-A13组小鼠伤后12、24 h肠道组织剪切型caspase-1、caspase-11蛋白表达明显减少（ P<0.05或 P<0.01）。伤后12 h，烫伤+LPS组小鼠肠道组织、血清IL-1β含量明显高于假伤组和单纯烫伤组（ P<0.01），烫伤+LPS+30 mg/kg LFM-A13组小鼠肠道组织、血清IL-1β含量明显低于烫伤+LPS组（ P<0.01）。 结论:BTK的磷酸化与烫伤脓毒症小鼠肠道组织剪切型caspase-1、caspase-11和血清、肠道的IL-1β含量增加有关。BTK的磷酸化介导了LPS诱导的烫伤小鼠肠道细胞焦亡，抑制BTK磷酸化可减轻烫伤小鼠肠道细胞焦亡，对肠道具有保护作用。

abstractsObjective:To investigate the role of Bruton's tyrosine kinase (BTK) in pyroptosis of intestinal cells caused by endotoxin/lipopolysaccharide (LPS) in scalded mice.Methods:The experimental research method was applied. One hundred and twenty-eight male C57BL/6 mice aged 6-8 weeks were divided into sham injury group, scald alone group, scald+LPS group, scald+LPS+3 mg/kg LFM-A13 group, scald+LPS+10 mg/kg LFM-A13 group, and scald+LPS+30 mg/kg LFM-A13 group. There were 8 mice in sham injury group, and there were 24 mice in the other 5 groups, respectively. Mice in 5 scald groups were inflicted with 10% total body surface area full-thickness scald on the back, and mice in sham injury group were sham injured on the back. At post injury hour (PIH) 0 (immediately), mice in sham injury group and scald alone group were intraperitoneally injected with normal saline, mice in scald+LPS group were intraperitoneally injected with LPS, and mice in scald+LPS+3 mg/kg LFM-A13 group, scald+LPS+10 mg/kg LFM-A13 group, and scald+LPS+30 mg/kg LFM-A13 group were intraperitoneally injected with LPS and LFM-A13 in corresponding doses. Mice in sham injury group were sacrificed at PIH 0 to collect serum and intestinal tissue, and 8 mice in each group of 5 scald groups were sacrificed at PIH 0, 12, and 24 to collect intestinal tissue and serum at PIH 12. Immunohistochemistry was used to detect phosphorylation of BTK in intestinal tissue of mice. Western blotting was used to detect the protein expressions of phosphorylated BTK (p-BTK), cleaved cysteine aspartic acid specific protease 1 (caspase-1), and cleaved caspase-11 in intestinal tissue of mice. Enzyme-linked immunosorbent assay method was used to detect interleukin-1β (IL-1β) in serum and intestinal tissue of mice. Data were statistically analyzed with one-way analysis of variance and least significant difference test.Results:There was no obvious phosphorylation of BTK in intestinal tissue of mice in 6 groups at PIH 0 and scald alone group at PIH 12 and 24. Phosphorylation of BTK in intestinal tissue of mice in scald+LPS group at PIH 12 and 24 were obviously increased compared with those in scald alone group. Phosphorylation of BTK in intestinal tissue of mice in scald+LPS+3 mg/kg LFM-A13 group, scald+LPS+10 mg/kg LFM-A13 group, and scald+LPS+30 mg/kg LFM-A13 group were obviously decreased compared with those in scald+LPS group, and the degrees of decline gradually increased with increase of dose in LFM-A13. Compared with (0.130±0.010) of sham injury group and (0.120±0.040 and 0.110±0.040) of scald alone group, protein expressions of p-BTK in intestinal tissue of mice in scald+LPS group at PIH 12 and 24 were obviously increased (0.470±0.090 and 0.430±0.080, P<0.01). Compared with those in scald+LPS group, protein expressions of p-BTK in intestinal tissue of mice in scald+LPS+3 mg/kg LFM-A13 group at PIH 24, and scald+LPS+10 mg/kg LFM-A13 group and scald+LPS+30 mg/kg LFM-A13 group at PIH 12 and 24 were obviously decreased (0.280±0.060, 0.300±0.120, 0.150±0.050, 0.280±0.090, 0.140±0.040, P<0.05 or P<0.01). Compared with those in scald+LPS+3 mg/kg LFM-A13 group, protein expressions of p-BTK in intestinal tissue of mice in scald+LPS+10 mg/kg LFM-A13 group and scald+LPS+30 mg/kg LFM-A13 group at PIH 24 were obviously decreased ( P<0.01). Compared with those in sham injury group and scald alone group, protein expressions of cleaved caspase-1 and caspase-11 in intestinal tissue of mice in scald+LPS group were obviously increased at PIH 12 and 24 ( P<0.01). Compared with those in scald+LPS group, protein expressions of cleaved caspase-1 at PIH 12 and cleaved caspase-11 at PIH 12 and 24 in intestinal tissue of mice in scald+LPS+3 mg/kg LFM-A13 group and protein expressions of cleaved caspase-1 and caspase-11 in intestinal tissue of mice in scald+LPS+10 mg/kg LFM-A13 group and scald+LPS+30 mg/kg LFM-A13 group at PIH 12 and 24 were obviously decreased ( P<0.01). Compared with those in scald+LPS+3 mg/kg LFM-A13 group, protein expressions of cleaved caspase-1 and caspase-11 in intestinal tissue of mice in scald+LPS+10 mg/kg LFM-A13 group and scald+LPS+30 mg/kg LFM-A13 group at PIH 12 and 24 were obviously decreased ( P<0.05 or P<0.01). At PIH 12, content of IL-1β in intestinal tissue and serum of mice in scald+LPS group were obviously higher than those in sham injury group and scald alone group ( P<0.01), and content of IL-1β in intestinal tissue and serum of mice in scald+LPS+30 mg/kg LFM-A13 group were obviously lower than those in scald+LPS group ( P<0.01). Conclusions:Phosphorylation of BTK is related to increases of cleaved caspase-1 and caspase-11 in intestinal tissue, and IL-1β content in intestinal tissue and serum of scalded septic mice caused by LPS. Phosphorylation of BTK mediates intestinal cell pyroptosis of scalded mice caused by LPS. Inhibiting phosphorylation of BTK can alleviate intestinal cell pyroptosis of scalded mice, with protective effect on intestinal injury intestine.