Abstract: Objective To explore the vascular smooth muscle cells (VSMCs) number and distribution in carotid atherosclerotic plaque and provide theoretical basis for clinical analysis of carotid atherosclerotic plaque stability. Methods 68 patients with carotid artery plaque after CEA were collected. All the surgical specimens were stained with Movat and immunochemistry to detect VSMCs, and the MA, MA/mm2 and the thickness of fibrous cap was counted under the microscope. Results The stable and unstable plaques were 87.5% and 12.5% in the asymptomatic group, 25.0% and 75.0% in the symptomatic group, respectively (P<0.001). MA of VSMCs in asymptomatic and symptomatic groups were 1650 +58, 1343 +54 (P<0.001); 1506 +59, 1312 +58 in stable and unstable plaques, respectively (P<0.05). In the distribution, the asymptomatic group and the symptomatic group were (1664±73) MA/mm2, (1112±69) MA/mm2 in basal part (P<0.001), (1697±76) MA/mm2, (1412±81) MA/mm2 in the shoulder part (P<0.05), (1620±65) MA/mm2, (1321±66) MA/mm2 in the fibrous cap (P<0.01), respectively. With the increase of fibrous cap, MA/mm2 of VSMCs also increased in both groups, showing a significant positive correlation (P<0.001). Conclusions The number and density of VSMCs in symptomatic and unstable plaques are less than those in asymptomatic and stable plaques. The thickness of fibrous cap is positively correlated with the density of VSMCs.

Key words: carotid atherosclerosis, smooth muscle cells, stroke, carotid endarterectomy