Ghrelin受体拮抗剂(D-Lys^(3))-GHRP-6减轻肥胖小鼠的脂肪炎症和氧化应激

Ghrelin receptor antagonist (D-Lys^(3))-GHRP-6 alleviates adipose inflammation and oxidative stress in obese mice

目的探讨Ghrelin受体拮抗剂(D-Lys3)-GHRP-6对高脂饮食(HFD)诱导的肥胖小鼠的脂肪炎症和氧化应激的改善作用及机制。方法4周龄雄性C57BL/6J小鼠随机分为常规饮食(RD)、高脂饮食(HFD)和HFD+(D-Lys3)-GHRP-6组。饲养16周后分析各组小鼠的体质量、体脂率和体脂成分,收集各组小鼠的血液和脂肪组织。酶联免疫吸附法检测小鼠单核细胞趋化蛋白1(MCP-1)、白细胞介素(IL)-6、肿瘤坏死因子-α(TNF-α)和IL-10。HE染色评估脂肪细胞直径及脂滴水平。免疫荧光染色及流式细胞术分析脂肪组织血管基质成分(SVF)巨噬细胞的数量及表型。检测各组血清中总超氧化物歧化酶(SOD)、丙二醛(MDA)、过氧化氢酶(CAT)、黄嘌呤氧化酶(XO)、谷胱甘肽过氧化物酶(GPx)、黄嘌呤脱氢酶(XDH)的活性。结果HFD组小鼠体质量、体脂率、附睾白色脂肪组织(eWAT)、皮下白色脂肪组织(sWAT)、肩胛间脂肪组织(iBAT)及脂肪细胞直径、iBAT脂滴水平均较RD组显著升高(P<0.05);但在HFD+(D-Lys3)-GHRP-6组上述指标较HFD组均有明显下降(P<0.05)。与HFD组相比,HFD+(D-Lys3)-GHRP-6组血清IL-6、TNF-α、MCP-1及MDA、XO和XDH活性均明显下降,而IL-10及SOD、CAT和GPx活性均升高(P<0.05);并且e WAT组织冠状结构(CLS)数、SVF中巨噬细胞总数、巨噬细胞M1表型下降而M2表型升高(P<0.05)。结论(DLys3)-GHRP-6可能通过抑制促炎性巨噬细胞募集并加速其M1表型向M2表型转换和维持氧化应激平衡来缓解HFD诱导的肥胖和脂肪炎症。

Objective To investigate the effect and mechanism of Ghrelin receptor antagonist(D-Lys3)-GHRP-6 on adipose inflammation and oxidative stress in high fat diet(HFD)-induced obese mice. Methods 4-week old male C57 BL/6 J mice were randomly divided into the normal diet(RD), high-fat diet(HFD) and HFD+(D-Lys3)-GhRP-6 groups. After 16 weeks of feeding, the body weight, body fat rate and body fat composition of mice in each group were analyzed, and the blood and adipose tissue of mice in each group were collected. Mouse monocyte chemokine 1(MCP-1), interleukin-6(IL-6), tumor necrosis factor-α(TNF-α) and IL-10 were detected by ELISA. HE staining was used to assess adipocyte diameter and lipid droplet level. Immunofluorescence staining and flow cytometry were used to analyze the number and phenotype of SVF macrophages in adipose tissue. The activities of total superoxide dismutase(SOD), malondialdehyde(MDA), catalase(CAT), xanthine oxidase(XO), glutathione peroxidase(GPx) and XDH in serum of each group were detected. Results Compared with RD group, mice body weight, body fat rate, epididymal white adipose tissue(eWAT), subcutaneous white adipose tissue(sWAT), interscapular brown adipose tissue(iBAT), diameter of fat cells and the fat droplet of iBAT all significantly increased in HFD group. However, the above indexes in HFD+(D-Lys3)-GHRP-6 group were significantly lower than those in HFD group(P<0.05). Compared with HFD group, serum IL-6, TNF-α, MCP-1, MDA, XO and XDH significantly reduced, while the activity of IL-10, SOD, CAT and GPx increased in HFD+(D-Lys3)-GHRP-6 group(P<0.05). In addition, the number of coronary structure(CLS) of eWAT tissue, the total number of macrophages in SVF and the M1 phenotype of macrophages markedly decreased while the M2 phenotype increased in the HFD+(D-Lys3)-GHRP-6 group(P<0.05). Conclusion(D-Lys3)-GhRP-6 may alleviate HFD-induced obesity and adipose inflammation by inhibiting the recruitment of pro-inflammatory macrophages, accelerating their M1-to-M2-phenotype conversion and maintaining the balance of oxidative stress.