高糖致血管功能损伤与血管内皮素和瘦素受体表达以及内皮素受体拮抗剂CPU0213的干预作用

High Glucose-induced Vascular Dysfunction and Expression of Vascular ET_AR and OB-Rb:Intervention Effects of ETR Antagonist CPU0213

目的:探究高糖引起的血管舒缩功能损害、血管内皮素受体(ETAR)和及瘦素受体(OB-Rb)mRNA表达水平的改变以及内皮素受体拮抗剂CPU0213的干预作用。方法:将大鼠颈椎脱位处死,分离取出其胸主动脉,剪成血管环,分别随机放入正常K-H液(正常对照组)、含33mol·L-1葡萄糖的K-H液(高糖模型组)以及含33mol·L-1葡萄糖和10-5mol·L-1 CPU0213的K-H液(CPU0213治疗组)中,温孵4小时。在各组温孵液中分别累积加入乙酰胆碱和去氧肾上腺素,测定各组血管环的最大舒张率和最大收缩值;在各组温孵液中分别加入L-硝基精氨酸,并重复去氧肾上腺素的收缩试验,测定各组血管NO生物利用度;通过RT-PCR实验,测定各组血管中ETAR和OB-Rb的mRNA表达水平。结果:与正常对照组相比,高糖模型组血管环的最大舒张率和NO生物利用度分别下降了44.7%(P<0.05)和27.2%(P<0.05),最大收缩值升高了32.9%(P<0.05),且其ETAR和OB-Rb的mRNA表达水平分别上调了111%(P<0.05)和97%(P<0.05);而与高糖模型组相比,CPU0213治疗组血管环的最大舒张率和最大收缩值以及NO生物利用度均有显著改善(P<0.05),并趋于正常,且其ETAR和OB-Rb的mRNA表达水平分别下调了33.6%(P<0.05)和13.4%(P>0.05)。结论:在高糖状态下,血管功能受损可能与血管组织内ETAR和OB-Rb mRNA表达水平上调有关,而ETR拮抗剂CPU0213能下调此时高水平表达的ETAR mRNA,并改善受损血管功能,表明ET系统明显调控血管功能;然而,受损血管组织在经CPU0213干预后,虽然其受损功能得到明显改善,但其OB-Rb mRNA表达水平没有明显改变,表明OB-Rb的表达可能对血管功能没有直接调控作用,且与ETAR并无直接关联。

Objective： To examine the high glucose-induced vascular dysfunction and alteration in expression levels of vascular endothelial receptor （ ETA R） and leptin receptor （OB-Rb） mRNA and the intervention effects of ETR antagonist CPU0213. Methods： Rats were sacrificed by dislocation of cervical vertebra. Segments of the thoracic aorta of rats were excised, cut into rings and randomly transferred to incubator filled respectively with normal K-H solution（ control group）, K-H solution plus 33 mol.L-1 glucose（ high glucose model group） and high glucose K-H solution plus 1 ×10-5 mol. L-1 CPU0213 （ CPU0213 treatment group）. After 4 hours＇ incubation, Phe and Ach were added to each group respec- tively and the maximum relaxation rate, contractive value and NO bioavailability were recorded. The expression levels of ETAR and OB-R_b mRNA were tested by RT-PCR. Results： Compared with the control group, the maximum relaxation rate and NO bioavailability of the rings in high glucose group decreased by 44.7% （ P 〈 0.05） and 27.2% （ P 〈 0. 05） respectively and the maximum contraction value thereof increased by 32. 9% （P 〈 0. 05）. After intervention with CPU0213, the maximum relaxation rate, contrac- tive value and NO bioavailability were improved significantly（ P 〈 0. 05） and tent to the normal. The levels of ETAR and OBRb mRNA in the high glucose group have been upregulated by 111% and 97% （P 〈 0. 05） compared with the control. However, the levels of ETAR and OBRb mRNA in the CPU0213 treat- ment group were decreased by 50. 6% （ P 〈 0. 05） and 13.4% （ P 〈 0. 05） respectively. Conclusion： Under the high glucose condition, the upregulated expression levels of vascular ETAR and OB-Rb mRNA may be associated with vascular dysfunction and ETR antagonist CPU0213 can reverse the upregulated ETAR mRNA level and improve the impaired vascular function, suggesting that the ET system modulates the vascular function significantly; however, after CPU0213 intervention, the upregulated OB-Rb mRNA level was changed obviously, suggesting that the OB-Rb expression may not directly act on vascular function and has no direct connection with ETAR.