目的  探讨肠源性尿毒症毒素氧化三甲胺(trimethylamine oxide，TMAO)对尿毒症大鼠c-Jun N端激酶(c-Jun N-terminal kinase，JNK)/B细胞淋巴瘤-2蛋白(B-cell lymphoma 2，Bcl-2)信号通路的调控作用及其在血管内皮细胞损伤中的机制。 方法  选取5周龄SD大鼠，建立尿毒症模型后分为模型组、TMAO组(3% TMAO)、SP600125组(15 mg/kg)及TMAO+SP组，并设假手术组(n=12)。检测体质量、24 h尿蛋白、血清肌酐(serum creatinine，Scr)和血尿素氮(blood urea nitrogen，BUN)。采用过碘酸-希夫染色(periodic acid-schiff staining，PAS)及苏木精-伊红染色(hematoxylin and eosin staining，HE)观察组织病理变化；实时荧光定量逆转录聚合酶链式反应(real-time quantitative reverse transcription polymerase chain reaction，RT-qPCR)及免疫组化(immunohistochemistry，IHC)检测内皮型一氧化氮合酶(endothelial nitric oxide synthase，eNOS)和血管细胞黏附分子-1(vascular cell adhesion molecule-1，VCAM-1)表达；酶联免疫吸附(enzyme-linked immunosorbent assay，ELISA)检测肿瘤坏死因子-α(tumor necrosis factor-α，TNF-α)、白细胞介素-1β(interleukin-1β，IL-1β)及白细胞介素-6(interleukin-6，IL-6)；检测超氧化物歧化酶(superoxide dismutase，SOD)、谷胱甘肽过氧化物酶(glutathione peroxidase，GSH-Px)及丙二醛(malondialdehyde，MDA)；末端脱氧核苷酸转移酶介导的缺口末端标记法(terminal deoxynucleotidyl transferase dUTP nick end labeling，TUNEL)检测细胞凋亡；蛋白印迹法(western blot，WB)检测Bcl-2相关X蛋白(Bcl-2-associated X protein，Bax)、半胱天冬酶-3(cysteine protease-3，Caspase-3)及磷酸化c-Jun N端激酶(phosphorylation of c-Jun N-terminal kinase，p-JNK)、磷酸化B细胞淋巴瘤-2蛋白(phosphorylation of B-cell lymphoma-2 protein，p-Bcl-2)表达。 结果  与假手术组相比，模型组Scr、BUN及尿蛋白水平升高(F=8.640、13.025、10.998，均P＜0.001)，eNOS表达降低、VCAM-1升高(F=21.951、20.080，均P＜0.001)，TNF-α、IL-1β、IL-6升高(F=10.678、32.043、21.181，均P＜0.001)，SOD、GSH-Px降低，MDA升高(F=14.172、11.445、13.984，均P＜0.001)，TUNEL阳性率及Bax、Caspase-3、p-JNK、p-Bcl-2表达升高(F=36.357、12.926、10.092、20.842、19.200，均P＜0.001)。TMAO进一步加重上述变化，SP600125可降低Scr、BUN及尿蛋白(F=8.640、13.025、10.998，均P＜0.001)，上调eNOS并下调VCAM-1表达(F=21.951、20.080，均P＜0.001)，降低TNF-α、IL-1β、IL-6水平(F=10.678、32.043、21.181，均P＜0.001)，提高SOD、GSH-Px活性并降低MDA水平(F=14.172、11.445、13.984，均P＜0.001)，同时降低TUNEL阳性率及Bax、Caspase-3、p-JNK、p-Bcl-2表达(F=36.357、12.926、10.092、20.842、19.200，均P＜0.001)。 结论  TMAO可通过激活JNK/Bcl-2信号通路，促进炎症反应、氧化应激及细胞凋亡，从而加重尿毒症大鼠血管内皮细胞损伤。

Objective  To investigate the regulatory effects of intestinal-derived uremic toxin trimethylamine oxide (TMAO) on the JNK/Bcl-2 signaling pathway and the mechanisms of vascular endothelial cell injury in uremic rats.  Methods  Five-week-old SD rats were selected and established as uremia models. The rats were divided into model group, TMAO group (3% TMAO), SP600125 group (15 mg/kg), TMAO+SP group, and sham operation control group (n=12). Body weight, 24-hour urinary protein, serum creatinine (Scr), and blood urea nitrogen (BUN) levels were measured. Histopathological changes were observed using PAS and HE staining. The expressions of endothelial nitric oxide synthase (eNOS) and vascular cell adhesion molecule-1 (VCAM-1) were detected by RT-qPCR and immunohistochemistry. Tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), and interleukin-6 (IL-6) were measured by ELISA. Superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), and malondialdehyde (MDA) were measured. Cell apoptosis was assessed by TUNEL method. The expressions of Bax, Caspase-3, p-JNK, and p-Bcl-2 were determined by western blot.  Results  Compared with the sham operation control group, the model group exhibited elevated Scr, blood BUN, and urinary protein (F=8.640, 13.025 and 10.998 respectively; P＜0.001), decreased eNOS expression and increased VCAM-1 expression (F=21.951, 20.080; P＜0.001), elevated TNF-α, IL-1β, and IL-6 (F=10.678, 32.043 and 21.181 respectively; P＜0.001), reduced SOD and GSH-Px activity with increased MDA level (F=14.172, 11.445 and 13.984 respectively; P＜0.001), and increased TUNEL positivity rate along with elevated Bax, caspase-3, p-JNK, and p-Bcl-2 (F=36.357, 12.926, 10.092, 20.842 and 19.200 respectively; P＜0.001). TMAO further exacerbated these pathological changes. SP600125 reversed the pathological changes in model group as described above, including reduced Scr, BUN, and urinary protein (F=8.640, 13.025 and 10.998 respectively; P＜0.001), upregulated eNOS expression and downregulated VCAM-1 expression (F=21.951, 20.080; P＜0.001), decreased TNF-α, IL-1β, and IL-6 (F=10.678, 32.043 and 21.181 respectively; P＜0.001), increased the activities of SOD and GSH-Px and reduced MDA level (F=14.172, 11.445 and 13.984 respectively; P＜0.001), decreased TUNEL positivity rate and the expressions of Bax, Caspase-3, p-JNK, and p-Bcl-2 (F=36.357, 12.926, 10.092, 20.842 and 19.200 respectively; P＜0.001).  Conclusion TMAO aggravates vascular endothelial cell injury in uremic rats by activating the JNK/Bcl-2 signaling pathway, thereby promoting inflammatory responses, oxidative stress, and apoptosis.