目的 探讨脂肪组织丝氨酸蛋白酶抑制剂(visceral adipose tissue-derived serpin, Vaspin)对脂肪组织巨噬细胞极化的影响，为Vaspin改善糖代谢提供新的理论依据。 方法 选取8周龄SD雄性大鼠50只，随机分为正常组(NC组)、2型糖尿病组(T2DM组)、不同浓度Vaspin干预组(V1：480 ng/kg、V2：960 ng/kg、V3：1 440 ng/kg)。Vaspin腹腔注射干预大鼠8周，干预结束后采集外周血分析糖脂代谢相关指标，通过腹腔注射葡萄糖耐量试验(intraperitoneal glucose tolerance test, IPGTT)、腹腔注射胰岛素耐量试验(intraperitoneal insulin tolerance test, IPITT)、高胰岛素-正葡萄糖钳夹技术评估各组大鼠糖耐量和胰岛素抵抗。通过免疫荧光技术(immunofluorescence, IF)测定附睾白色脂肪组织(epididymal white adipose tissue, eWAT)中CD11c、CD206、PPARγ荧光表达；实时荧光定量PCR(real-time polymerase chain reaction，RT-PCR)测定eWAT CD11c和CD206及肿瘤坏死因子(TNF)-α、白细胞介素(IL)-1β及IL-10的mRNA表达水平；酶联免疫吸附试验(enzyme linked immunosorbent assay，ELISA)检测血清中TNF-α、IL-1β及IL-10的浓度；免疫印迹法(Western blotting，WB)检测eWAT中iNOS、Arg-1、p-Akt、Akt和PPARγ的蛋白表达。 结果 干预8周后，各组的体重及血脂水平差异无统计学意义，IPGTT、IPITT及高胰岛素-正葡萄糖钳夹实验显示Vapsin干预组血糖及胰岛素敏感性改善，且呈剂量依赖性(P<0.05)；IF及RT-PCR显示Vaspin可下调eWAT中CD11c、IL-1β、TNF-α的表达，上调CD206、IL-10、PPARγ的表达，且与Vaspin干预浓度相关(P<0.05)；ELISA显示Vaspin干预可下调血清中IL-1β、TNF-α的浓度，上调IL-10的浓度(P<0.05)；WB显示Vaspin可下调iNOS蛋白的表达，上调Arg1、p-Akt及PPARγ的表达，且呈剂量依赖性(P<0.05)。 结论 Vaspin通过上调巨噬细胞PPARγ通路，使脂肪组织巨噬细胞向M2型极化，改善脂肪组织炎症因子谱，从受体后水平改善胰岛素抵抗，从而改善T2DM大鼠的糖耐量。 Objective This study aimed to explore the effect of Vaspin on adipose tissue macrophage polarization and its underlying mechanism. Methods Fifty male SD rats, aged 8 weeks, were chosen and randomly allocated into three groups: the normal control(NC), the type 2 diabetes(T2DM), and various concentrations of Vaspin intervention(V1: 480 ng/kg, V2: 960 ng/kg, V3: 1 440 ng/kg). Vaspin was administered via intraperitoneal injection for 8 weeks. Glucose tolerance and insulin sensitivity were evaluated via intraperitoneal glucose tolerance test(IPGTT), intraperitoneal insulin tolerance test(IPITT) and hyperinsulinemic-euglycemic clamp. Adipose tissue inflammation and macrophage polarization were assessed using immunofluorescence, RT-PCR and western blotting. Results After 8 weeks of intervention, there were no statistically significant differences in body weight and blood lipid levels among groups. IPGTT, IPITT, and hyperinsulinemic-euglycemic clamp experiments demonstrated that Vaspin intervention improved blood glucose and insulin sensitivity, exhibiting a dose-dependent manner(P<0.05). IF and RT-PCR showed that Vaspin downregulated the expression of CD11c, IL-1β, and TNF-α in eWAT, while upregulating the expression of CD206, IL-10, and PPARγ, which correlated with Vaspin concentration(P<0.05). ELISA revealed that Vaspin intervention reduced the concentrations of IL-1β and TNF-α in serum, while increasing the concentration of IL-10(P<0.05). Western blotting demonstrated that Vaspin downregulated iNOS protein expression, while upregulating Arg1, p-Akt, and PPARγ expression in a dose-dependent manner(P<0.05). Conclusion Vaspin promotes M2 polarization of adipose tissue macrophages via PPARγ pathway, leading to reduced inflammation and improved insulin sensitivity in T2DM rats.
Vaspin improves insulin sensitivity in type 2 diabetes rats by regulating the polarization of adipose tissue macrophages
Objective This study aimed to explore the effect of Vaspin on adipose tissue macrophage polarization and its underlying mechanism. Methods Fifty male SD rats, aged 8 weeks, were chosen and randomly allocated into three groups: the normal control(NC), the type 2 diabetes(T2DM), and various concentrations of Vaspin intervention(V1: 480 ng/kg, V2: 960 ng/kg, V3: 1 440 ng/kg). Vaspin was administered via intraperitoneal injection for 8 weeks. Glucose tolerance and insulin sensitivity were evaluated via intraperitoneal glucose tolerance test(IPGTT), intraperitoneal insulin tolerance test(IPITT) and hyperinsulinemic-euglycemic clamp. Adipose tissue inflammation and macrophage polarization were assessed using immunofluorescence, RT-PCR and western blotting. Results After 8 weeks of intervention, there were no statistically significant differences in body weight and blood lipid levels among groups. IPGTT, IPITT, and hyperinsulinemic-euglycemic clamp experiments demonstrated that Vaspin intervention improved blood glucose and insulin sensitivity, exhibiting a dose-dependent manner(P<0.05). IF and RT-PCR showed that Vaspin downregulated the expression of CD11c, IL-1β, and TNF-α in eWAT, while upregulating the expression of CD206, IL-10, and PPARγ, which correlated with Vaspin concentration(P<0.05). ELISA revealed that Vaspin intervention reduced the concentrations of IL-1β and TNF-α in serum, while increasing the concentration of IL-10(P<0.05). Western blotting demonstrated that Vaspin downregulated iNOS protein expression, while upregulating Arg1, p-Akt, and PPARγ expression in a dose-dependent manner(P<0.05). Conclusion Vaspin promotes M2 polarization of adipose tissue macrophages via PPARγ pathway, leading to reduced inflammation and improved insulin sensitivity in T2DM rats.
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