大麻制剂HU210对实验性急性胰腺炎的干预作用及其与Toll样受体4信号通路的可能关系

目的:研究大麻类制剂HU210对雨蛙肽(caerulein,CAE)诱导的野生型(wild-type,WT)和Toll样受体4基因敲除(tlr4~(-/-))小鼠急性胰腺炎(acute pancreatitis,AP)的干预作用,并探讨其作用机制。方法:将成年C57BL/10J小鼠及相同背景的tlr4~(-/-)小鼠各随机分成3组:AP组、AP+HU210组及正常对照组。小鼠腹腔注射CAE(50μg·kg~(-1)·h~(-1))6次及脂多糖(10 mg/kg)1次复制AP模型;AP+HU210组在造模前及造模后各腹腔注射1次HU210(50μg/kg);对照组注射生理盐水替代CAE和脂多糖。造模处理后3 h,取血处死小鼠,取胰腺、肺组织及肠道Peyer’s结。结果:与对照组相比,无论在WT或tlr4~(-/-)小鼠,AP造模后胰腺病理评分,血浆淀粉酶活性,血浆IL-6、TNF-α及MCP-1水平,以及肺MPO活性均明显升高(P0.05),P38蛋白表达明显上调(P0.05)。同时,AP造模后,与WT小鼠相比,tlr4~(-/-)小鼠血浆IL-6、TNF-α及MCP-1水平,以及胰腺P38及p-P38蛋白表达均明显降低(P0.05),Peyer’s结CD3~+、CD4~+T淋巴细胞百分比及CD4~+/CD8~+比值明显降低(P0.05)。HU210干预使2种小鼠AP模型的胰腺病理学评分和肺MPO活性的升高明显得到改善(P0.05);在WT小鼠,而非tlr4~(-/-)小鼠,AP引起的血浆淀粉酶活性和胰腺P38及p-P38蛋白表达的变化在HU210干预后明显逆转(P0.05)。结论:TLR4主要参与AP全身炎症反应,其机制可能依赖TLR4-P38 MAPK信号通路;大麻制剂HU210对AP的干预主要通过抑制炎症细胞的浸润发挥组织保护作用,与TLR4信号通路的关系似乎不明显。

Effects of cannabinoid HU210 on experimental acute pancreatitis and possible relationship with Toll-like receptor 4 signaling pathway

AIM: Using Toll-like receptor 4 gene knockout (tlr4^-/-) mice and the wild-type (WT) mice with the same C57BL/10J genetic background, the effects of HU210, a cannabis preparation, on caerulein (CAE)-induced acute pancreatitis (AP) and the potential mechanisms were investigated.METHODS: WT or tlr4^-/- mice were randomly divided into AP group, AP+HU210 group and control group. AP was induced by intraperitoneal injection of CAE (50 μg·kg^-1·h^-1) for a total of 6 times and lipopolysaccharide (LPS) at 10 mg/kg 6 h after the first injection of CAE. HU210 (50 μg/kg) was given 30 min before and 4 h after the first injection of CAE in AP+HU210 group. The animals in control group were given normal saline instead of CAE and LPS in the same way. The mice were sacrificed 3 h after the last injection. The blood, the pancreas, the lungs and the intestinal Peyer's patches were harvested.RESULTS: Compared with control group, the pancreatic pathological score and P38 protein expression, plasma amylase activity and inflammatory mediator levels, and lung MPO activity were significant increased (P<0.05) in both WT and tlr4^-/- mice with AP. Compared with the WT mice with AP, the tlr4^-/- mice with AP showed significantly low levels of IL-6, TNF-α and MCP-1 in the plasma, low expression levels of pancreatic P38 and p-P38 protein (P<0.05), and mild alterations of CD3⁺ T-lymphocytes, CD4⁺ T-lymphocytes and the ratio of CD4⁺/CD8⁺(P<0.05). The administration of HU210 attenuated the pancreatic pathological changes and the lung MPO activity in both stains of mice with AP (P<0.05). However, the inhi-bitory effects of HU210 on the increased amylase activity in the plasma and the increased protein levels of pancreatic P38 and p-P38 were remarkable (P<0.05) in WT mice instead of in tlr4^-/- mice.CONCLUSION: TLR4 is mainly involved in AP-related systemic inflammatory response and its mechanism may be dependent on TLR4-P38 MAPK signaling pathway. The intervention of HU210 in AP plays a protective role mainly by inhibiting the infiltration of inflammatory cells, and the relationship with TLR4 signaling pathway is not obvious.