RESUMO
AIM:To explore the effects of endothelial indoleamine 2,3-dioxygenase (IDO) on the migration and the expression of contractile proteins in the pericytes.METHODS: Human pulmonary artery endothelial cells ( HPAECs) and rat cerebral microvascular pericytes were cultured in vitro.Over-expression of IDO in the HPAECs ( IDO-HPAECs) was established.The pericytes were treated with HPAEC-conditioned medium (control group), IDO-HPAEC conditioned medium (treatment group), or IDO-HPAECs-conditioned medium containing 1-methyl-DL-tryptophan (1-mT) ( inhibition group) .The concentrations of nitric oxide ( NO) , tryptophan and kynurenine in the co-culture system were de-termined.The viability, migration and the expression of the contractile proteins in the pericytes were compared.RE-SULTS:No statistical difference of the pericyte viability after treatment with IDO-HPAEC-conditioned medium at 6~48 h was observed (P>0.05).The migratory ability of the pericytes significantly decreased in treatment group compared with control group (P0.05).The concentration of tryptophan was significantly lower in treatment group than that in control group (P<0.01), and significantly higher in in-hibition group than that in treatment group (P<0.01).The concentration of kynurenine was significantly higher in treat-ment group than that in control group (P<0.01), and significantly lower in inhibition group than that in treatment group (P<0.01).The expression ofα-smooth muscle actin and desmin was significantly lower in treatment group than that in control group (P<0.01), and significantly higher in inhibition group than that in treatment group (P<0.01).CON-CLUSION:Endothelial IDO inhibits the migration and the expression of the contractile proteins in the pericytes, and may play essential roles in the regulation of microvasculatures.