| Backgroud:Diabetic vascular complications greatly increase the rate of morbidity and mortality of diabetic patients. Studies have shown that the essence of diabetic vascular complication is vascular inflammation. The abnormal adhesion function of monocytes and vascular endothelial cell is a prerequisite for early vascular inflammation response. It is known that the disorders of adhesion and secretion dysfunction are the initiating factors in atherosclerosis, which play an important role in macro-vascular lesions.Rhein is the monomer extracted from rhubarb, which is about 284 g/mol. It contains anti-inflammatory, anti-tumor, anti-bacterial, anti-oxidantive effects and so on. In recent years, several studies have shown that rhein can relieve the proliferation of glomerular mesangial cells and inhibit inflammatory response in patients suffering diabetic nephropathy. It can improve the conditions of early diabetic nephropathy obviously. While the effects of rhein on vascular endothelial adhesion function are rarely studied. This research aims at exploring the effects of rhein on endothelial adhesion and secretion functions, which relays on studying endothelial adhesion molecules and related vasoactive substance in animal and cellular experiment.Methods:1、Animal experiment1.1 Fourteen db/db mice aged 4 weeks were randomly assigned into Rhein group and db/db group(n=7 per group).These animals were treated with Rhein at 100mg/kg/d(dissolved in 1% sodium carboxymethyl cellulose) or 1% sodium carboxymethyl cellulose for 8 weeks. In addition, another seven age-matched lean non-diabetic C57BL/KsJW/w littermates served as a wild-type control.1.2 Body weight and random blood glucose were measured every week. The levels of sICAM-1、sVCAM-1、ET-1、NO in serum were assayed by ELISA, the protein expressions of ICAM-1、VCAM-1 were detected by immunochemistry, the mRNA expressions of ICAM-1、VCAM-1、ET-1、eNOS were detected by RT-PCR.2、Cellular experiment:2.1 HUVECs were divided into five groups of Control(CTL), TNF-a(treated with TNF-a 40ng/ml), Rhein 100(treated with Rhein 100ug/ml plus TNF-a 40ng/ml), Rhein50(treated with Rhein 50ug/ml plus TNF-a 40ng/ml), Rhein 10(treated with Rhein lOug/ml plus TNF-a 40ng/ml). The HUVECs were treated with Rhien of various concentrations for 24 hours plus TNF-a 40ng/ml for 6 hours.2.2 The mRNA and protein expressions of Intercellular adhesion molecule-1 (ICAM-1) were detected by RT-PCR and Western blotting respectively, the adhesive function of HUVECs were detected by monocytic cells.Results:1、Animal experiment1.1 Immunochemistry: Compared with negative group, Rhein could inhibit the protein expressions of adhesive molecules like ICAM-1, VCAM-1 in thoracic aorta (P<0.05).1.2 RT-PCR: Compared with negative group, Rhein could inhibit the mRNA expressions of ICAM-1,VCAM-1,ET-1 (P<0.05) and increase the level of eNOS mRNA in thoracic aorta (P<0.05)1.3 ELISA:Compared with negative group, Rhein could inhibit the levels of sICAM-1、sVCAM-1 (P<0.05) and increase the level of NO in serum, while it has no effect on the level of ET-1 (P>0.05).2、Cellular experiment2.1 RT-PCR and Western blot:Compared with group TNF-a, the expression of ICAM-1 protein was decreased in groups of Rhein100、Rhein50、Rhein10 (P<0.05); the level of ICAM-1 mRNA were decreased in groups of Rhein50、Rhein100.2.2 Adhesive experiment: The number of adhesive monocytic THP-1 cells was decreased in group Rhein100.Conclusions:1、Rhein can inhibit the mRNA expression of ICAM-1、VCAM-1、ET-1 and increase the level of NO in db/db mouse. It increase the level of NO in serum, while it decrease the levels of sICAM-1、sVCAM-1 in serum and the protein expressions of ICAM-1 and VCAM-1 in thoracic aorta in animal experiment.2、The expression of ICAM-1 protein and mRNA of HUVECs were decreased by Rhein in cellular experiment.3、Rhein can reduce the expression of adhesion molecules, regulate the secretion of vascular active substances, and relieve vascular inflammtion, which provide bases for the use of Rhein on diabetic vascular complication. |
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