The effect of blue light exposure on the expression of circadian genes: Bmall and Cryptochrome 1 in peripheral blood mononuclear cells of jaundiced neonates

Abstract

The purpose of this study was to investigate the effect of blue light phototherapy on the expression of circadian genes in peripheral blood mononuclear cells (PBMC) and plasma melatonin levels in neonates. Real-time reverse-transcriptase polymerase chain reaction (RT-PCR) was used to determine the expression of Bmall and Cry1 in PBMC, and an enzyme-linked immunosorbent assay was used to determine plasma melatonin levels in 32 breast-milk jaundiced neonates before and after phototherapy, compared with 29 control neonates. The results showed that the expression of Bmall was decreased and Cry1 increased significantly after phototherapy. Plasma melatonin levels were decreased after phototherapy. There was no statistical difference in Bmall and Cry1 gene expression and plasma melatonin levels in the control group. In conclusion, phototherapy does affect the expression of the circadian genes Bmall and Cry1 in PBMC and plasma melatonin concentration in jaundiced neonates. Our results suggest that phototherapy should be timed according to circadian rhythms when treating jaundiced neonates. Copyright © 2005 International Pediatric Research Foundation, Inc.