Astragaloside IV Inhibits Proliferation and Promotes Apoptosis in Rat Vascular Smooth Muscle Cells under High Glucose Concentration in vitro

Abstract

Astragaloside IV is one of the main active ingredients of Radix astragali, which is a herbal remedy widely used in traditional Chinese medicine for the treatment of diabetes and cardiovascular diseases. However, its effects on vascular smooth muscle cell (VSMC), which plays a key role in the development of diabetic vascular complications, were not well studied. The present study was performed to examine the effects of astragaloside IV on proliferation, apoptosis and phenotypic modulation of VSMC under high D-glucose (25 mM). Application of astragaloside IV inhibited the proliferation and the rise of the proliferation index (PI) of VSMC induced by high glucose in a dose-dependent manner. Astragaloside IV induced apoptosis in VSMC under high glucose conditions, accompanied with typical morphological alterations and loss of mitochondrial membrane potential (ΔΨ _m). In addition, Western blot analysis revealed that astragaloside IV increased the expression of α-smooth muscle actin, an important phenotypic modulation marker. In conclusion, astragaloside IV could inhibit high glucose-induced VSMC proliferation through intervention with the cell cycle, promoting apoptosis and regulating phenotypic modulation of VSMC, which strongly suggest that astragaloside IV could hinder the process of pathological vascular remodeling in diabetic patients.

Abbreviations

α-SMA:alpha-smooth muscle actin

AS-IV:astragaloside IV

DMEM:Dulbecco's modified Eagle's medium

EDTA:ethylenediaminetetraacetic acid

FCS:fetal calf serum

FITC:fluorescein isothiocyanate

HG:high glucose

NG:normal glucose

PBS:phosphate-buffered saline

PI:proliferative index

RSG:rosiglitazone

SDS:sodium dodecyl sulfate

SDS-PAGE:sodium dodecylsulfate polyacrylamide gel electrophoresis

VSMC:vascular smooth muscle cells

Key words

astragaloside IV - high glucose - vascular smooth muscle cell (VSMC) - proliferation - apoptosis - vascular remodeling

References

• 1 Beckman J A, Creager M A, Libby P. Diabetes and atherosclerosis: epidemiology, pathophysiology, and management.  JAMA. 2002;  287 2570-81
• 2 Wilson P W, Cupples L A, Kannel W B. Is hyperglycemia associated with cardiovascular disease? The Framingham Study.  Am Heart J. 1991;  121 586-90
• 3 Gibbons G H, Dzau V J. The emerging concept of vascular remodeling.  N Engl J Med. 1994;  330 1431-8
• 4 Alipui C, Ramos K, Tenner TE J r. Alterations of rabbit aortic smooth muscle cell proliferation in diabetes mellitus.  Cardiovasc Res. 1993;  27 1229-32
• 5 Bennett M R, Boyle J J. Apoptosis of vascular smooth muscle cells in atherosclerosis.  Atherosclerosis. 1998;  138 3-9
• 6 Owens G K. Regulation of differentiation of vascular smooth muscle cells.  Physiol Rev. 1995;  75 487-517
• 7 Wu F, Chen X. A review of pharmacological study on Astragalus membranaceus (Fisch.).  Bge Zhong Yao Cai. 2004;  27 232-4
• 8 Li H B, Ge Y K, Zhang L, Zheng X X. Astragaloside IV improved barrier dysfunction induced by acute high glucose in human umbilical vein endothelial cells.  Life Sci. 2006;  79 1186-93
• 9 Xu M E, Xiao S Z, Sun Y H, Ou-Yang Y, Zheng X X. Effects of astragaloside IV on pathogenesis of metabolic syndrome in vitro.  Acta Pharmacol Sin. 2006;  27 229-36
• 10 Jiang Q L, Wang Y L, Sheng J P. Effect of astragaloside IV on glucagon-like peptide-1.  Chin J Gerontol. 2003;  23 52-3
• 11 Ruef J, Liu S Q, Bode C, Tocchi M, Srivastava S, Runge M S. et al . Involvement of aldose reductase in vascular smooth muscle cell growth and lesion formation after arterial injury.  Arterioscler Thromb Vasc Biol. 2000;  20 1745-52
• 12 Schiffrin E L. Peroxisome proliferator-activated receptors and cardiovascular remodeling.  Am J Physiol Heart Circ Physiol. 2005;  288 H1037-43
• 13 Hsueh W A, Jackson S, Law R E. Control of vascular cell proliferation and migration by PPAR-gamma: a new approach to the macrovascular complications of diabetes.  Diabetes Care. 2001;  24 392-7
• 14 Wakino S, Kintscher U, Kim S, Yin F, Hsueh W A, Law R E. Peroxisome proliferator-activated receptor gamma ligands inhibit retinoblastoma phosphorylation and G1→S transition in vascular smooth muscle cells.  J Biol Chem. 2000;  275 22 435-41
• 15 Gouni-Berthold I, Berthold H K, Weber A A, Ko Y, Seul C, Vetter H. et al . Troglitazone and rosiglitazone induce apoptosis of vascular smooth muscle cells through an extracellular signal-regulated kinase-independent pathway.  Naunyn Schmiedebergs Arch Pharmacol. 2001;  363 215-21
• 16 Natarajan R, Gonzales N, Xu L, Nadler J L. Vascular smooth muscle cells exhibit increased growth in response to elevated glucose.  Biochem Biophys Res Commun. 1992;  187 552-60
• 17 Orlov S N, Pchejetski D, Taurin S, Thorin-Trescases N, Maximov G V, Pshezhetsky A V. et al . Apoptosis in serum-deprived vascular smooth muscle cells: evidence for cell volume-independent mechanism.  Apoptosis. 2004;  9 55-66
• 18 Huang Z, Guo K J, Guo R X, He S G. Effects of 5-fluouracil combined with sulfasalazine on human pancreatic carcinoma cell line BxPC-3 proliferation and apoptosis in vitro.  Hepatobil Pancreat Dis Int.. 2007;  6 312-20
• 19 Mosmann T. Rapid colorimetric assay for cellular growth and survival: application to proliferation and cytotoxicity assays.  J Immunol Methods. 1983;  65 55-63
• 20 Hong H, Liu G Q. Protection against hydrogen peroxide-induced cytotoxicity in PC12 cells by scutellarin.  Life Sci. 2004;  74 2959-73
• 21 Ruiz E, Gordillo-Moscoso A, Padilla E, Redondo S, Rodriguez E, Reguillo F. et al . Human vascular smooth muscle cells from diabetic patients are resistant to induced apoptosis due to high Bcl-2 expression.  Diabetes. 2006;  55 1243-51
• 22 Sakuma H, Yamamoto M, Okumura M, Kojima T, Maruyam T, Yasuda K. High glucose inhibits apoptosis in human coronary artery smooth muscle cells by increasing bcl-xL and bfl-1/A1.  Am J Physiol Cell Physiol. 2002;  283 C422-8
• 23 Wagner H, Bauer R, Xiao P G, Chen J M, Michler G. Radix astragali (Huang Qi).  Chin Drug Monographs Anal. 1997;  1 1-17
• 24 Ohkawara S, Okuma Y, Uehara T, Yamagishi T, Nomura Y. Astrapterocarpan isolated from Astragalus membranaceus inhibits proliferation of vascular smooth muscle cells.  Eur J Pharmacol. 2005;  525 1-7
• 25 Kockx M M, Knaapen M W. The role of apoptosis in vascular disease.  J Pathol. 2000;  190 267-80
• 26 Boivin W A, Granville D J. Detection and quantification of apoptosis in the vasculature.  Methods Mol. Med2007;  139 181-96
• 27 Ross R. The pathogenesis of atherosclerosis: a perspective for the 1990 s.  Nature. 1993;  362 801-9
• 28 Kocher O, Gabbiani F, Gabbiani G, Reidy M A, Cokay M S, Peters H. et al . Phenotypic features of smooth muscle cells during the evolution of experimental carotid artery intimal thickening. Biochemical and morphologic studies.  Lab. Invest1991;  65 459-70
• 29 Moreno P R, Fallon J T, Murcia A M, Leon M N, Simosa H, Fuster V. et al . Tissue characteristics of restenosis after percutanous transluminal coronary angioplasty in diabetic patients.  J Am Col Cardiol. 1999;  34 1045-9
• 30 Haller H, Lindschau C, Quass P, Distler A, Luft F C. Differentiation of vascular smooth muscle cells and the regulation of protein kinase C-alpha.  Circ Res. 1995;  76 21-9