激活多巴胺I类受体对氧化性低密度脂蛋白诱导的人单核细胞THP-1分泌NO/NOS的影响

目的：探讨激活多巴胺Ⅰ类受体（DR1）对氧化型低密度脂蛋白（ox-LDL）诱导的人单核细胞（THP-1）分泌一氧化氮/一氧化氮合酶（NO/NOS）的影响及可能机制。方法：THP-1细胞经佛波酯PMA诱导分化，分为正常对照组（control），氧化型低密度脂蛋白处理组（ox-LDL），DR1激动剂干预组（SKF），DR1阻断剂干预组（SCH），ERK阻断剂干预组（PD98059）；应用油红O染色法鉴定泡沫细胞；硝酸还原法检测NO、NOS的变化情况；免疫荧光和Western blot检测各组细胞蛋白表达情况。结果：ox-LDL刺激48 h可形成泡沫细胞；DR1在THP1细胞上表达，ox-LDL刺激后，DR1蛋白表达降低（P<0.01）；激活DR1受体能够明显抑制由ox-LDL引起的NO、iNOS增多（P<0.01）；在MAPK阻断剂PD98059存在的情况下，SKF的作用部分丧失。结论：激活DR1受体可抑制ox-LDL引起的THP-1细胞NO的大量产生，此过程可能由ERK信号通路所介导。

Effects of activation of dopamine type I receptor on the produc-tion of NO/NOS in ox-LDL activated THP-1 cells

Objective:To study the effect of excited dopamine type I receptor on the production of nitric oxide/nitric oxide synthase(NO/NOS)in ox-LDL activated THP-1 cells and the possible mechanism. Methods:Cultured THP-1 cells activated by PMA were randomly assigned in the following groups:control group (control), oxidized low density lipoprotein group (ox-LDL), dopamine receptor 1(DR1) agonist group (SKF), DR1 antagonist group (SCH), ERK blocker group (PD98059). Oil Red O staining was used to identify the accumulation of cellular lipid. The levels of NO and NOS in the supernatant of THP-1 were assayed by nitrate reductase method. The protein expression of DR1, p-ERK and ERK were obtained by Western blot and immunity fluorescence. Results:After 48 h of incubation of ox-LDL, accumulation of lipid in the cytoplasm was found in most THP-1 cells. Compared with control group, DR1 protein expression was reduced in ox-LDL-induced cells(P<0.01). Activation of DR1 agonist decrease the production of NO and iNOS(P<0.01), and PD98059 partly reversed the above effect. Conclusion:Activation of DR1 can inhibit the production of NO/NOS in ox-LDL-induced THP-1 cells, which may be related with ERK pathway.