目的:探讨消皮素D（GSDMD）在重症急性胰腺炎（SAP）小鼠肠道损伤中的作用机制。方法:将C57BL/6小鼠按随机数字表法分为生理盐水（NS）组、小干扰RNA（siRNA）-NS组、SAP模型组和siRNA-SAP组，每组6只。通过腹腔注射雨蛙素50 μg/kg联合脂多糖（LPS）10 mg/kg构建SAP小鼠模型；NS组给予等量NS；siRNA-SAP组和siRNA-NS组在制模或注射NS前分3次经尾静脉注射siRNA 50 mg/kg。制模12 h后取各组小鼠眼球血，采用酶联免疫吸附试验（ELISA）检测血清白细胞介素（IL-1β、IL-18）水平。处死小鼠观察腹腔内大体改变；取胰腺和回肠组织，光镜下观察胰腺及肠黏膜病理学改变；采用反转录-聚合酶链反应（RT-PCR）检测肠道组织长链非编码RNA uc.173（lnc uc.173）表达；采用免疫组化法检测肠黏膜上皮细胞紧密连接蛋白带状闭锁蛋白-1（ZO-1）及闭合蛋白（Occludin）的表达；采用蛋白质免疫印迹试验（Western blotting）检测肠道组织GSDMD蛋白表达。结果:ELISA显示，SAP模型组血清IL-1β、IL-18水平较NS组和siRNA-NS组明显升高〔IL-1β（ng/L）：146.66±1.40比44.48±5.76、81.49±10.75，IL-18（ng/L）：950.47±177.09比115.43±16.40、84.84±21.90，均n P<0.05〕；siRNA-SAP组IL-1β、IL-18水平较SAP模型组明显降低〔IL-1β（ng/L）：116.26±15.54比146.66±1.40，IL-18（ng/L）：689.96±126.08比950.47±177.09，均n P<0.05〕。大体观察显示，NS组和siRNA-NS组小鼠腹腔内未见明显异常；SAP模型组和siRNA-SAP组可见肠道有不同程度水肿、充血，但siRNA-SAP组损伤较SAP模型组明显减轻。光镜下显示，NS组和siRNA-NS组胰腺未见明显变化，肠黏膜未见明显损伤；SAP模型组和siRNA-SAP组胰腺组织有不同程度水肿、炎性细胞浸润、小叶结构破坏，回肠可见不同程度的肠黏膜破坏和绒毛断裂，但siRNA-SAP组病理损伤较SAP模型组明显减轻。RT-PCR显示，SAP模型组肠道组织lnc uc.173表达较NS组和siRNA-NS组显著降低（2n -ΔΔCt：0.26±0.12比1.01±0.37、0.67±0.32，均n P<0.05）；而siRNA-SAP组lnc uc.173表达较SAP组明显升高（2n -ΔΔCt：0.60±0.39比0.26±0.12，n P<0.05）。免疫组化显示，NS组ZO-1、Occludin均沿肠黏膜上皮细胞分布，并呈强阳性表达；SAP模型组和siRNA-SAP组ZO-1、Occludin表达均明显减弱，但siRNA-SAP组较SAP模型组有所增强。Western blotting显示，SAP模型组肠道组织GSDMD蛋白表达水平较NS组和siRNA-NS组明显升高〔GSDMD蛋白（GSDMD-N/β-actin）：1.99±0.46比1、1.00±0.78，均n P<0.05〕；与SAP模型组相比，siRNA-SAP组GSDMD蛋白表达明显下降〔GSDMD蛋白（GSDMD-N/β-actin）：1.42±0.42比1.99±0.46，n P<0.05〕。n 结论:SAP小鼠全身炎症反应和肠黏膜屏障损伤可能与肠道组织GSDMD表达升高有关，GSDMD通过介导细胞焦亡促进炎性因子释放，导致肠道损伤，下调肠上皮细胞紧密连接蛋白ZO-1及Occludin的表达，致使肠道黏膜损伤。“,”Objective:To investigate the function of gasdermin D (GSDMD) in intestinal damage of mice with severe acute pancreatitis (SAP).Methods:The healthy C57BL/6 mice were divided into four groups randomly, including normal saline (NS) group, small interfering RNA (siRNA)-NS group, SAP model group and siRNA-SAP group, with 6 mice in each group. The SAP mouse model was reproduced by intraperitoneal injection of caerulein 50 μg/kg combined with lipopolysaccharide (LPS) 10 mg/kg; the NS group was given the same amount of NS; in the siRNA-SAP group and siRNA-NS group, siRNA 50 mg/kg was injected through the tail vein three times before modeling or injection of NS. The blood of mice eyeball in each group was taken 12 hours after modeling, and serum interleukins (IL-1β, IL-18) levels were detected by enzyme linked immunosorbent assay (ELISA). The mice were sacrificed to observe the general changes in abdominal cavity, the pancreas and ileum tissues were taken to observe the pathological changes under a light microscope. The expression of long-chain non-coding RNA uc.173 (lnc uc.173) was detected by reverse transcription-polymerase chain reaction (RT-PCR). Immunohistochemical method was used to detect the expression of tight junction proteins zonula occluden-1 (ZO-1) and Occludin in intestinal mucosal epithelial cells. Western blotting was used to detect the GSDMD protein expression level in the intestinal tissue.Results:The serum levels of IL-1β and IL-18 in the SAP model group were significantly higher than those in the NS group and the siRNA-NS group [IL-1β (ng/L): 146.66±1.40 vs. 44.48±5.76, 81.49±10.75, IL-18 (ng/L): 950.47±177.09 vs. 115.43±16.40, 84.84±21.90, alln P < 0.05]; and the levels of IL-1β and IL-18 in the siRNA-SAP group were significantly lower than those in the SAP model group [IL-1β (ng/L): 116.26±15.54 vs. 146.66±1.40, IL-18 (ng/L): 689.96±126.08 vs. 950.47±177.09, both n P < 0.05]. General observation showed that there were no obvious abnormalities in the abdominal cavity of the mice in the NS and siRNA-NS groups; the mice in the SAP model group and the siRNA-SAP group had different degrees of edema and congestion in the intestine; compared with the SAP model group, the abnormalities in the siRNA-SAP group was significantly reduced. Under light microscope, there were no obvious changes in the pancreas and intestinal mucosa in the NS group and the siRNA-NS group; the pancreatic tissue of the SAP model group and the siRNA-SAP group had different degrees of edema, inflammatory cell infiltration, and lobular structure damage, and the intestinal mucosa was damaged to a certain degree, and the villi were broken to varying degrees, but the damage in the siRNA-SAP group was lighter. The results of RT-PCR showed that the expression of lnc uc.173 in the intestinal tissues of the model SAP group was significantly lower than that of the NS group and the siRNA-NS group (2 n -ΔΔCt: 0.26±0.12 vs. 1.01±0.37, 0.67±0.32, both n P < 0.05), while the expression of lnc uc.173 in the siRNA-SAP group was significantly higher than that in the SAP model group (2 n -ΔΔCt: 0.60±0.39 vs. 0.26±0.12, n P < 0.05). Immunohistochemistry showed that ZO-1 and Occludin proteins in the NS group were distributed along the epithelial cells of the intestinal mucosa, showing a strong expression; ZO-1 and Occludin expressions were significantly reduced in the SAP model group and siRNA-SAP group, but the expressions in the siRNA-SAP group was higher than that in the SAP model group. Western blotting showed that the expression level of GSDMD protein in the intestinal tissues of the SAP model group was significantly higher than that of the NS group and the siRNA-NS group [GSDMD protein (GSDMD-N/β-actin): 1.99±0.46 vs. 1, 1.00±0.78, both n P < 0.05]. Compared with the SAP model group, the expression of GSDMD protein in the siRNA-SAP group was significantly decreased [GSDMD protein (GSDMD-N/β-actin): 1.42±0.42 vs. 1.99±0.46, n P < 0.05].n Conclusions:The systemic inflammatory response and intestinal mucosal barrier damage of SAP mice may be related to the increase of GSDMD expression in intestinal tissues. GSDMD mediates cell pyrolysis to promote the release of inflammatory factors, cause intestinal injury, and down-regulate the expression of intestinal epithelial cell tight junction proteins such as ZO-1 and Occludin, resulting in intestinal mucosal damage.