Houttuynia cordata polysaccharide alleviates chronic vascular inflammation by suppressing calcium-sensing receptor in rats

The present study explored activities of orally administrated Houttuynia cordata polysaccharide (HCP) on vascular chronic inflammation which was established by a tail-vein injection of lipopolysaccharide (LPS) once weekly for 6 weeks in rats. Results showed that administration of HCP significantly alleviated chronic inflammation by reducing white blood cell and monocyte counts, together with repairing histological impairment of vascular tissue. Furthermore, vascular protections of HCP were in association with decrease of MDA content, pro-inflammatory cytokines interleukin-1beta (IL-1β) and tumor necrosis factor-α (TNF-α), and enhancement of the activities of antioxidant enzyme superoxide dismutase, catalase, glutathione peroxidase activities. Moreover, HCP exhibited anti-inflammatory responses evidenced by reducing the expressions of Toll-like receptor 4 (TLR4) and NF-kB P65. Meanwhile, the combination of HCP and LPS reduced calcium concentration and CaSR mRNA expression in the vascular tissue. Collectively, these results indicated that HCP suppressed LPS-induced chronic vascular inflammation via calcium-sensing receptor and TLR4/NF-kB pathways in rats.