Objective To examine the effects of L
arginine and nimodipine on the
expression of monocyte chemoattractant protein 1
(MCP 1) mRNA and
protein induced by lipopolysaccharide (LPS) in endothelial cells (ECs). Methods After 8 hour exposure to LPS, LPS+L arginine and LPS+nimodipine respectively, the total RNA in ECs was extracted by the guanidinium isothiocyanate method. The MCP 1 mRNA
expression in ECs was examined by Dot blot analysis using a γ 32 P end labeled 35 mer oligonucleotide probe of MCP 1. MCP 1 protein in the EC conditioned media (EC CM) was determined by sandwich ELISA for each group. The expression of MCP 1 protein in ECs was examined immunocytochemically. Results Dot blotting showed that after exposure to LPS, the integral absorbance ( A ) value of the dots of MCP 1 mRNA on the nitrocellulose membrane were 3.14, which was 2.5 fold as much as that in the control group (A=1.24). The A values of the LPS+L arginine group and the LPS+nimodipine group were 1.43 and 1.65, respectively. ELISA showed that the MCP 1 protein content in the EC CM of the LPS group was 6.29±0.53 ng/ml, which was markedly higher than that of the control group (2.32±0.16) ng/ml ( P <0.01). The MCP 1 protein content in the EC CM of the LPS+L arginine group and the LPS+nimodipine group was significantly lower than that of the LPS group ( P <0.01). Furthermore, the ECs in LPS group showed a strong immunoreactivity for the polyclonal MCP 1 antibody, whereas the ECs in control, L arginine and nimodipine groups revealed a weak postive immunostaining. Conclusion L arginine and nimodipine can markedly inhibit the expression of MCP 1 in ECs induced by LPS.