Upregulation of TRPC1/6 may be involved in arterial remodeling in rat.

BACKGROUND: Hypertension and its complications are associated with arterial remodeling. Transient receptor potential cationic channels (TRPCs) are important nonselective cationic channels that regulate calcium homeostasis in mammalian cell membranes. We aimed to study the expression of various TRPC isoforms in spontaneously hypertensive rat (SHR) carotid arterial remodeling and explore the relationship between SHR carotid arterial remodeling and TRPC expression.

MATERIALS AND METHODS: Thirty male SHRs were randomly divided into three groups and sacrificed at ages 4, 8, and 18 wk, respectively, with matching control male Wistar-Kyoto rats (n = 10). Caudal artery systolic blood pressure (SBP) was measured every 2 wk. Carotid artery remodeling parameters including carotid artery wall thickness (MT), lumen diameter (LD), medial area, collagen area rate, and average nuclear area in media cells were determined after histologic staining. Real-time polymerase chain reaction and immunoblot assays were performed to assess TRPC expression. Carotid artery remodeling and TRPC expression were reevaluated after ginsenoside Rb1 treatment from eighth to eighteenth week.

RESULTS: Carotid artery remodeling of SHRs was aggravated gradually with age and SBP, as well as MT, LD, MT/LD, medial area, average nuclear area in media cells, and collagen deposition, most obvious at 18 wk. Interestingly, expression of TRPC1, 3, and 6 increased with age and SBP, with TRPC1/6 showing significant differences between the Wistar-Kyoto and 18 wk groups; TRPC4/5 expression was unchanged and TRPC7 was barely detected. Importantly, after ginsenoside Rb1 treatment, TRPC1/6 expressions were significantly inhibited, SBP decreased, and the carotid artery remodeling in SHRs relieved.

CONCLUSIONS: Upregulation of TRPC1 and TRPC6 may be involved in carotid arterial remodeling in SHRs.