多氯联苯118对大鼠胰岛素敏感性影响的研究

目的探讨多氯联苯（polychlorinated biphenyl，PCB）118对大鼠胰岛素敏感性的影响。方法将40只清洁级成年雄性Wistar大鼠[体重（200±10）g]按随机数字表法分为4组，每组10只，除正常对照组外，其余3组给予不同剂量PCB118：低、中、高剂量组分别为10、100、1000μg·kg^-1·d^-1，每周腹腔注射5d，造模13周后行腹腔葡萄糖耐量试验（IPGTT），计算糖负荷后30min胰岛素增值与血糖增值比值（△I30／△G30）、葡萄糖、胰岛素曲线下面积（AUCg、AUCi）、AUCi／AUCg及稳态模型胰岛素抵抗指数（HOMA—IR）。采用单因素方差分析进行多组间均数比较。结果低、中、高剂量组空腹胰岛素水平[（19．0±7．1）、（18．5±3．1）、（22．1±1．2）mU／L]、30min胰岛素[（55．0±1．9）、（55．0±2．4）、（72．3±1．0）mU／L]及30min血糖水平[（22．32±2．44）、（19．87±1．89）、（21．90±2．88）mmol／L]明显高于对照组[（10．05±3．59）、（25．68±1．27）mU／L、（17．08±1．35）mmol／L]，差异有统计学意义（F值分别为3．622、8．798、7．024，均P〈0．05）；高剂量组60、120min胰岛素水平高于对照组[60min（46．3±1．2）比（18．1±1．1）mU／L，t=3．287，P〈0．05；120min（39．5±1．3）比（24．5±9．4）mU／L，t=2．435，P〈0．05]，各剂量组△I30／AGmAUCi、AUCi／AUCg明显高于对照组（F值分别为15．548、7．130、5．509，均P〈0．05），低、中、高剂量组HOMA—IR亦明显高于对照组（1．26±0．42、1．35±0．22、1．52±0．47比0．65±0．37，F=6．937，P〈0．05），上述指标在各剂量组问比较差异无统计学意义（均P〉0．05）。结论低剂量PCB118持续暴露可能引起大鼠胰岛素敏感性降低。

Effects of polychlorinated biphenyl 118 on the insulin sensitivity in Wistar rats

Objective To investigate the effects of polychlorinated biphenyl （PCB） 118 on the insulin sensitivity in rats. Methods Forty male Wistar rats were randomly divided into 4 groups： solvent control group, low dose, medium dose, high dose group （PCB118 0, 10, 100, 1000 μg·kg^-1·d^-1）, respectively, with PCB118 iutraperitoneally for five consecutive days per week. After 13 weeks, an intraperitoneal glucose tolerance test （IPGTT） was performed, and the ratio of increment insulin to glucose concentration at 30 min after the glucose loaded （△I30/△G30）, area under the curve （AUC） of glucose （AUCg）, AUC of insulin （AUCi）, AUCi/AUCg and homeostasis model assessment of insulin resistance （HOMA-IR） were calculated. One-way analysis of variance （ANOVA） was used for data analysis. Results Compared with the controls, fasting insulin levels and insulin and blood glucose levels at IPGTF 30 min were significantly increased in all the PCB118-treated groups （ fasting insulin levels ： （ 19.0 ± 7. 1 ）, （ 18.5 ± 3.1）, （22. 1 ±1.2） vs （10.0±3.6） mU/L; insulin levels at IPGTT 30 min： （55.0 ±1.9）, （55.0 ± 2.4）, （72.3.±1.0） vs （25.7.±1.3） mU/L; blood glucose levels at IPGTT 30 min： （22.3±2.4）,（ 19. 87 ± 1.89） , （21.90 ± 2. 88） vs （ 17.08 ± 1.35 ） mmol/L, F values were 3. 622, 8. 798 and 7. 024, respectively, all P 〈 0. 05 ）. Insulin levels at IPGTT 60 min and 120 rain were significantly increased only in high dose group （60 min： （46. 2 ± 1.2） vs （18.1 ± 1.1） mU/L, t =3. 287, P 〈0. 05; 120 min： （39. 5 ± 1.3） vs （24.5 ± 9.4） mU/L, t = 2. 435, P 〈 0.05）. △I30/△G30, AUCi and AUCi/AUCg were dramatically increased in all the PCB118-treated groups （F values were 15.548, 7. 130 and 5.509, respectively, all P 〈 0. 05）. HOMA-IR were also dramatically increased in all the PCB118-treated groups （1.26±0.42, 1.35 ±0.22, 1.52 ±0.47 vs 0.65 ±0.37, F=6.937, P 〈0.05）. However, these indicators showed no significant difference among the PCB118-treated groups （P 〉 0. 05）. Conclusion Continuous exposure to a low dose of PCB118 could reduce insulin sensitivity in rats.