J Korean Diabetes Assoc.  2003 Jun;27(3):253-259.

Effect of Glucose Concentrations on the Cell Proliferation and Expression of L-type Calcium Channel mRNA in Cultured Rat Aortic Vascular Smooth Muscle Cells

• Cho YJ
• Yoo HJ
• Nam HW
• Suh JY
• Jeong IK
• Ihm SH
• Kim HK
• Park CY
• Yoo JM
• Kim DM
• Choi MG
• Park SW

Abstract

BACKGROUND: Vascular smooth muscle cell (VSMC) proliferation is one of the major pathogenic mechanisms for atherosclerosis. It is known that L-type calcium channels play a role in VSMC proliferation in diabetic rats. However, there have been no studies that show an association between the L-type calcium channels and the VSMC proliferation due to various glucose concentrations in the culture media. Therefore, the association between the voltage-dependent L-type calcium channels of the VSMCs, and the growth of vascular smooth muscle cells, was examined.
METHODS
Rat aortic VSMCs were isolated from the aorta of Sprague-Dawley and OLETF rats, using an enzymic method. The VSMCs were cultured in various concentrations of glucose (5.5, 11.0, 16.6, 25, 30 and 40 mM). The VSMCs (1x10(4) cells in 24-well plates) were incubated in the presence of Bay K 8644 (10(-6)M), both with and without verapamil (10(-6)M), for 48 hours. The proliferation was then assessed by the MTT (methylthiazole tetrazolium) assay, and the expression of L-type calcium channel mRNA by RT-PCR.
RESULTS
The vascular smooth muscle cell proliferation was significantly increased, in a dose-dependent manner, with glucose concentrations below 25 mM in both in a dose-dependent manner, with glucose concentrations below 25 mM in both kinds of rat. However, the increase in the VSMC proliferation of the OLETF rat was significantly higher than in the Sprague-Dawley rat. After the Bay K 8644 treatment, with the same glucose concentration, the VSMC proliferation and the expression of L-type calcium channel mRNA were significantly increased in both kinds of rat. After treatment with verapamil, the increased VSMC proliferation and expression of L-type calcium channel mRNA, due to the Bay K 8644, were suppressed to control levels in both kinds of rat.
CONCLUSION
The results suggest that below certain concentrations of glucose, 25 mM, the L-type calcium channels may play a role in the VSMC proliferation of OLETF and Sprague-Dawley rats. The growth of the VSMCs in OLETF rats, due to various glucose concentrations (< 25 mM), was significantly higher than in the Sprague-Dawley rats.

Keyword

Vascular smooth muscle cells; Proliferation; L-type calcium channel; Glucose concentrations

MeSH Terms

3-Pyridinecarboxylic acid, 1,4-dihydro-2,6-dimethyl-5-nitro-4-(2-(trifluoromethyl)phenyl)-, Methyl ester
Animals
Aorta
Atherosclerosis
Calcium Channels, L-Type*
Cell Proliferation*
Culture Media
Glucose*
Muscle, Smooth, Vascular*
Rats*
Rats, Inbred OLETF
Rats, Sprague-Dawley
RNA, Messenger*
Verapamil
3-Pyridinecarboxylic acid, 1,4-dihydro-2,6-dimethyl-5-nitro-4-(2-(trifluoromethyl)phenyl)-, Methyl ester
Calcium Channels, L-Type
Culture Media
Glucose
RNA, Messenger
Verapamil