Expression of TRPC in the smooth muscle cells of the small intramyocardial arteries in the left ventricles of spontaneously hypertensive rats

Abstract

Abstract: AIM: To investigate the relationship between the remodelling of small intramyocardial arteries(SIMAs) and the expression of transient receptor potential channel (TRPC) in spontaneously hypertensive rats (SHR).METHODS: 24-weeks-old male of SHR taken as the experimental group (SHR group,n=8 ), and the wistar-kyoto rats (WKY,n=8) with matching age and male systolic blood pressure (SBP) is normal as the control group. Left ventriclar mass index (LVMI) was calculated to evaluate the hypertrophy degree of the left ventricle. The structure feature of the small intramyocardial arteries with diameters from 10 to 69 μm in the left ventricles was evaluated with HE staining.The wall area (WA), lumen area (LA), wall area/lumen area (WA/LA) of SIMAs were measured. Vascular smooth muscle cells (VSMCs) were recognized with alpha-smooth muscle actin (α-SMA) immunofluorescence staining.The expression of TRPC1, TRPC3, TRPC5, TRPC6 were also detected with immunofluorescence staining.RESULTS: Both SBP and LVMI of the SHR group were significantly higher than those in WKY group 〔(200±4) vs (118±9) mm Hg;(3.11±0.03) vs (2.42±0.10) mg/g respectively,both P<0.05〕. Both WA and WA/LA of the SHR group were larger than those in WKY group〔(2951±224) vs (2654±190) μm²;(2.01±0.04) vs (1.53±0.03),both P﹤0.05 〕. However, LA of the SHR group was smaller than that of WKY group〔(1469±117) vs (1730±98) μm² ,P<0.05〕. Positive α-SMA immunofluorescence staining indicated that the thickening middle layer of the SIMAs was smooth muscle cells. The expressions of TRPC1 and TRPC3 on the SIMAs of SHR group were significantly higher than those in WKY group(65±8 vs 28±3 and 60±4 vs 26±8 respectively,both P<0.05). The expressions of TRPC5 in two groups were not statistically different(28±7 vs 28±7,P>0.05). TRPC6 was not expressed on the SIMAs in both groups.CONCLUSION: The smooth muscle cells of the small intramyocardial arteries in 24-weeks-old SHR expresses TRPC1,TRPC3 and TRPC5 but not TRPC6. The remodelling of the small intramyocardial arteries in SHR is associated with the up-regulation of TRPC1 and TRPC3.

Key words: Small intramyocardial arteries, Vascular remodeling, Vascular Smooth muscle cell, Transient receptor potential channel, Spontaneously hypertensive rats

CLC Number:

R965.2

XUE Wan-wan, HONG Hua-shan, LIN Xiao-hong, LIN Jun-hua, FANG Mei-qin. Expression of TRPC in the smooth muscle cells of the small intramyocardial arteries in the left ventricles of spontaneously hypertensive rats[J]. Chinese Journal of Clinical Pharmacology and Therapeutics, 2013, 18(8): 879-884.

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