Table 2. Collagen fiber area percentage and smooth muscle cell proliferation index of tunica media of carotid arteries of rats in each group (n = 6, mean ± SD).

Grouping	Collagen fiber area percentage (%)	Smooth muscle cell proliferation index (%)
Sham-operated	15.35 ± 4.446	1.84 ± 0.519
Model	67.53 ± 7.684a	35.31 ± 12.969a
Amlodipine	48.62 ± 10.175b	4.79 ± 1.184c
Enalapril	30.69 ± 9.140c	3.73 ± 0.423c
Combination	32.23 ± 12.008d,e	3.15 ± 0.543d,e

^aP < 0.01 vs. sham-operated group; ^bP < 0.05, ^cP < 0.01, vs. model group; ^dP > 0.05 vs. Enalapril group; ^eP < 0.05 vs. Amlodipine group. MT: media thickness; LD: lumen diameter; RHR: renovascular hypertensive rat.