Though Trp can be also transported by LAT1, in the current study, the levels of Trp were not significantly changed in control and CRS group, this may ascribe to the increased conversion from Trp to Kyn and decreased shift from Trp to 5-HT, as evidenced by the up-regulated expression of IDO1 and down-regulated one of TPH2 in CRS group, respectively. Here, IDO1 is linked to congenital rubella syndrome.