In vivo and in vitro inhibitory effects of a traditional Chinese formulation on LPS-stimulated leukocyte-endothelial cell adhesion and VCAM-1 gene expression

Aim of the study

A traditional Chinese formulation Huang-Lian-Jie-Du-Tang (HLJDT) exerts anti-inflammatory effects. The present study aimed to investigate the effect of HLJDT on the LPS-stimulated leukocyte–endothelial cell adhesion and VCAM-1 gene expression both in vivo and in vitro.

Materials and methods

HLJDT was extracted from rhizoma coptidis, radix scutellariae, cortex phellodendri and fructus gardeniae in a weight rario of 1:1:1:1. In vivo leukocyte–endothelial cell adhesion was observed in rat lung after LPS stimulation (5 mg/kg, i.p.) with or without HLJDT (350 or 700 mg/kg, i.g.) pretreatment. The protein expression of vascular cell adhesion molecule 1 (VCAM-1) was analyzed by immunohistochemical method. In vitro leukocyte–endothelial cell adhesion was performed by examining the adhesion of THP-1 cells to LPS-stimulated human vascular endothelial cells with or without HLJDT pretreatment. The VCAM-1 expression at the RNA and protein levels was investigated by RT-PCR and western blot analysis, respectively. The activation of NF-κB was examined by the nuclear translocation of NF-κB by immunocytochemical method.

Results

In vivo, HLJDT dose-dependently reduced the number of leukocytes adhered to endothelium and VCAM-1 protein expression in lung venules of LPS-challenged rats. In vitro, HLJDT dose-dependently decreased the number of THP-1 cells adhered to LPS-stimulated endothelial cells and the expression of VCAM-1 both at the RNA and protein levels. The LPS-induced nuclear translocation of NF-kappa B in endothelial cells was also dose-dependently inhibited by HLJDT.

Conclusions

The present study demonstrated an additional mechanism underlying the anti-inflmmatory effect of HLJDT by inhibiting the leukocyte–endothelial cell adhesion and VCAM-1 gene expression. The inhibition of NF-kappa B activation by HLJDT might suggest a profound anti-inflammatory consequences.