大麻素2 型受体激动剂对脓毒症大鼠急性肾损伤的影响*

Effects of cannabinoid receptor 2 agonist on acute renal injury in septic rats*

摘要:

目的 探讨大麻素2型受体激动剂对脓毒症大鼠急性肾损伤的影响。方法 选取健康成年雄性SD 大鼠24 只，按照随机数字表法将大鼠分为假手术组（Sham 组）、脓毒症组（Sep 组）、脓毒症+CB2R 激动剂 JWH133组（Sep+JWH133组），每组8只。采用盲肠结扎穿孔法复制脓毒症大鼠模型，Sep+JWH133组于术后 1 h腹腔注射JWH133 1.5 mg/kg，Sham组和Sep组分别于上述时间点腹腔注射等量生理盐水，模型复制24 h后， 心脏采血。采用ELISA法检测血清肌酐（Scr）水平；HE染色法观察小肠组织及肾脏组织病理改变；免疫组织化 学法测定肾脏自噬相关蛋白Beclin-1、Atg5的表达水平。结果 光镜下Sham组为正常小肠和肾脏组织，无出血 及炎症浸润，小肠组织损伤程度为0级。Sep组小肠绒毛上皮组织缺失或连续性中断，黏膜血管出血，炎症细胞 大量浸润，组织损伤程度≥3级；肾脏近端小管上皮细胞排列紊乱，肾小球体积明显增大，系膜细胞肿胀，间 质有明显出血及大量炎症细胞浸润。Sep+JWH133组病理改变明显减轻，小肠绒毛上皮组织较完整，仅有少许 血管出血，少量炎症细胞浸润，组织损伤程度≤2 级；肾脏结构较完整，间质仅有少量出血及炎症细胞浸润。 Sep 组和Sep+JWH133 组Scr、肾小管Paller 评分较Sham 组升高（P <0.05），Sep+JWH133 组SCr、肾小管Paller 评分较Sep 组降低（P <0.05）。Sep 组和Sep+JWH133 组自噬相关蛋白Beclin-1 和Atg5 的表达较Sham 组上调 （P <0.05），Sep+JWH133 组Beclin-1 和Atg5 的表达较Sep 组上调（P <0.05）。结论 大麻素2 型受体激动剂可 以减轻脓毒症大鼠急性肾损伤，其作用机制可能与诱导肾脏自噬表达上调有关。

Abstract:

Objective To investigate the effects of cannabinoid receptor 2 (CB2R) agonist on acute renal injury in septic rats. Methods Twenty-four healthy adult male SD rats were divided into sham operation group (Sham group), sepsis group (Sep group), and sepsis + CB2R agonist JWH133 group (Sep + JWH133 group) (n =8 in each group) according to the random number table method. The cecal ligation and puncture method was used to establish a rat sepsis model. The Sep + JWH133 group was intraperitoneally injected with JWH133 1.5 mg/kg one hour after surgery. The Sham group and the Sep group were given the same amount of saline at the same time. After 24 h of modeling, the blood samples were collected via cardiac puncture. ELISA was used to detect serum creatinine (Scr) levels. The small intestine and kidney tissues were HE stained and the pathological changes were observed under light microscope. Immunohistochemical method was applied to determine the expression levels of autophagyrelated proteins including Beclin-1 and Atg5. Results Under light microscope, the small intestine and kidney tissues in the Sham group were normal, with no bleeding or inflammatory infiltration, and the degree of small intestinal injury was grade 0. In Sep group, the villous epithelium of the small intestine was absent or interrupted, with mucosal hemorrhage and a large number of inflammatory cells infiltration, and the degree of tissue injury was greater than grade 3. The disordered arrangement of renal proximal tubular epithelial cells, significantly-enlarged glomeruli, swollen mesangial cells, and obvious hemorrhage and a large number of inflammatory cells infiltration in the interstitium were seen in the kidney tissues. In Sep+JWH133 group, the pathological changes were alleviated obviously, where the villous epithelium of small intestine was intact, with only a little bleeding and a small amount of inflammatory cells infiltration, and the degree of tissue injury was less than grade 2. The structure of kidney was intact, and there was only a small amount of hemorrhage and inflammatory cells infiltration in the interstitium. Compared with the Sham group, the Scr value and the Paller's score of the Sep group and the Sep + JWH133 group were significantly increased (P < 0.05), while Beclin-1 and Atg5 expression levels were increased (P < 0.05). Compared with the Sep group, the Scr value and Paller's score of the Sep + JWH133 group were decreased (P < 0.05), whereas the expression levels of Beclin-1 and Atg5 were further increased (P < 0.05). Conclusions CB2R agonists may reduce acute kidney injury in septic rats by enhancing autophagy in the kidney.