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目的:探讨芍药苷对脓毒症心脏微血管内皮细胞（CMECs）通透性的影响及机制。方法:体外分离并原代培养大鼠CMECs细胞，待细胞进入对数生长期用于实验。采用四甲基偶氮唑盐比色法（MTT）筛选出芍药苷的安全有效浓度10、20、40 μmol/L。将细胞分为空白对照组、脂多糖（LPS）组及低、中、高浓度芍药苷预处理组。空白对照组用完全培养基培养；LPS组在完全培养基中加入1 mg/L的LPS刺激细胞；芍药苷预处理各组分别于LPS刺激前4 h加入10、20、40 μmol/L芍药苷进行预处理。各组细胞于LPS刺激后继续培养24 h，采用辣根过氧化物酶（HRP）法检测大鼠CMECs细胞通透性；采用酶联免疫吸附试验（ELISA）检测细胞上清液中CXC趋化因子配体（CXCL1、CXCL2）水平；采用实时荧光定量反转录-聚合酶链反应（RT-qPCR）检测细胞中CXCL1、CXCL2的mRNA表达；采用蛋白质免疫印迹试验（Western Blot）检测细胞中磷酸化Src（p-Src）、血管内皮-钙黏蛋白（VE-cadherin）、磷酸化丝裂素活化蛋白激酶（p-MAPK）的蛋白表达。结果:与空白对照组相比，LPS组大鼠CMECs细胞通透性明显增加；经不同浓度芍药苷预处理后细胞通透性均有一定程度改善，以40 μmol/L芍药苷组改善最明显，与LPS组比较差异有统计学意义（n A值：1.61±0.07比2.13±0.06，n P<0.01）。ELISA结果显示，空白对照组大鼠CMECs细胞上清液中有适量CXCL1、CXCL2分泌；但在LPS诱导下，细胞上清液中CXCL1、CXCL2分泌量明显增加；给予不同浓度芍药苷预处理后细胞上清液中CXCL1、CXCL2的分泌量均明显减少，其中40 μmol/L芍药苷对CXCL1的抑制作用最佳，20 μmol/L芍药苷对CXCL2的抑制作用最佳，与LPS组比较差异均有统计学意义〔CXCL1（ng/L）：337.51±68.04比829.86±65.06，CXCL2（ng/L）：4.48±0.11比9.41±0.70，均n P<0.01〕。RT-qPCR结果显示，大鼠CMECs细胞中CXCL1、CXCL2的mRNA表达与ELISA结果一致，表现为LPS能够诱导大鼠CMECs细胞中CXCL1、CXCL2的mRNA表达增加；而不同浓度芍药苷预处理后能够明显降低CXCL1、CXCL2的mRNA表达，40 μmol/L芍药苷对CXCL1 mRNA表达的抑制效果最佳，20 μmol/L芍药苷对CXCL2 mRNA表达的抑制效果最佳，与LPS组比较差异均有统计学意义〔CXCL1 mRNA（2n -ΔΔCt）：0.543±0.004比0.812±0.089，CXCL2 mRNA（2n -ΔΔCt）：10.52±0.71比17.68±1.09，均n P<0.01〕。Western Blot结果显示，空白对照组大鼠CMECs细胞中有适量p-Src、VE-cadherin和p-MAPK蛋白表达；LPS刺激后大鼠CMECs细胞中p-Src、p-MAPK蛋白表达明显增加，而VE-cadherin蛋白表达明显下降；经不同浓度芍药苷预处理后，细胞中p-Src、p-MAPK蛋白表达有不同程度降低，但VE-cadherin蛋白表达则呈升高趋势，以40 μmol/L芍药苷组效果最佳，与LPS组比较差异均有统计学意义〔p-Src蛋白（p-Src/GAPDH）：1.02±0.09比1.29±0.05，p-MAPK蛋白（p-MAPK/GAPDH）：0.24±0.02比0.62±0.02，VE-cadherin蛋白（VE-cadherin/GAPDH）：0.64±0.03比0.31±0.02，均n P<0.01〕。n 结论:芍药苷能够通过调节CMECs细胞中Src/VE-cadherin通路，抑制炎症相关蛋白及趋化因子的表达和分泌，改善LPS诱导的CMECs细胞通透性。“,”Objective:To investigate the effect and mechanism of paeoniflorin on the permeability of cardiac microvascular endothelial cells (CMECs) in sepsis.Methods:Primary rat CMECs were isolated and cultured n in vitro, and the cells in the logarithmic growth phase were used for experiments. Tetramethylazozolium colorimetry (MTT) was used to screen the safe and effective concentrations of paeoniflorin at 10, 20, and 40 μmol/L. The cells were divided into blank control group, lipopolysaccharide (LPS) group and low, medium and high concentration paeoniflorin pretreatment group. The cells in the blank control group were cultured in complete medium; the cells in the LPS group were challenged with LPS (1 mg/L) in complete medium; and the cells in the paeoniflorin pretreatment groups were pretreated with 10, 20, and 40 μmol/L paeoniflorin at 4 hours before LPS stimulation. The cells in each group were further cultured for 24 hours after LPS stimulation. The horseradish peroxidase (HRP) method was used to detect the permeability of rat CMECs. The enzyme-linked immunosorbent assay (ELISA) was used to detect the CXC chemokine ligand (CXCL1, CXCL2) levels in the cell supernatant. The real-time fluorescence quantitative reverse transcription-polymerase chain reaction (RT-qPCR) was used to detect the mRNA expressions of CXCL1 and CXCL2 in the cells. Western Blot was used to detect phosphorylated Src (p-Src), vascular endothelial-cadherin (VE-cadherin) and phosphorylated mitogen activated protein kinase (p-MAPK).n Results:Compared with the blank control group, the permeability of rat CMECs in the LPS group was significantly increased. The cell permeability was improved to some extent after paeoniflorin pretreatment at different concentrations, and the improvement was most obvious in the 40 μmol/L paeoniflorin group, with statistically significant difference as compared with the LPS group ( n A value: 1.61±0.07 vs. 2.13±0.06, n P < 0.01). ELISA results showed that there were moderate amounts of CXCL1 and CXCL2 in the cell supernatant of rat CMECs in the blank control group. However, the secretion of CXCL1 and CXCL2 in the cell supernatant was increased significantly under the induction of LPS. After pretreatment with paeoniflorin at different concentrations, the secretion of CXCL1 and CXCL2 in the cell supernatant was significantly reduced. The most obvious inhibitory effect on CXCL1 was 40 μmol/L paeoniflorin, and the most obvious inhibition on CXCL2 was 20 μmol/L paeoniflorin, the differences were statistically significant as compared with the LPS group [CXCL1 (ng/L): 337.51±68.04 vs. 829.86±65.06, CXCL2 (ng/L): 4.48±0.11 vs. 9.41±0.70, both n P < 0.01]. RT-qPCR results showed that the mRNA expressions of CXCL1 and CXCL2 in the rat CMECs were consistent with the ELISA results. LPS could increase mRNA expressions of CXCL1 and CXCL2 in the rat CMECs, and pretreatment with different concentrations of paeoniflorin could significantly reduce the mRNA expressions of CXCL1 and CXCL2. The 40 μmol/L paeoniflorin had the best inhibitory effect on CXCL1 mRNA expression, and the 20 μmol/L paeoniflorin had the best inhibitory effect on CXCL2 mRNA expression, the differences were statistically significant as compared with the LPS group [CXCL1 mRNA (2 n -ΔΔCt): 0.543±0.004 vs. 0.812±0.089, CXCL2 mRNA (2n -ΔΔCt): 10.52±0.71 vs. 17.68±1.09, both n P < 0.01]. Western Blot results showed that moderate amounts of p-Src, VE-cadherin and p-MAPK proteins were expressed in the rat CMECs in the blank control group. After LPS stimulation, the expressions of p-Src and p-MAPK proteins were increased significantly, while the expression of VE-cadherin protein was decreased significantly. After pretreatment with different concentrations of paeoniflorin, the expressions of p-Src and p-MAPK proteins in the cells were decreased to varying degrees, while the expression of VE-cadherin protein was increased, and 40 μmol/L paeoniflorin had the most obvious effect, the differences were statistically significant as compared with the LPS group [p-Src protein (p-Src/GAPDH): 1.02±0.09 vs. 1.29±0.05, p-MAPK proteins (p-MAPK/GAPDH): 0.24±0.02 vs. 0.62±0.02, VE-cadherin protein (VE-cadherin/GAPDH): 0.64±0.03 vs. 0.31±0.02, all n P < 0.01].n Conclusion:Paeoniflorin can regulate the Src/VE-cadherin pathway in CMECs, inhibit the expression and secretion of inflammation-related proteins and chemokines, and improve the cell permeability of CMECs induced by LPS.