Phototherapy motivates protein and lipid oxidation in jaundiced term and late term neonates

Background: Hyperbilirubinemia is one of the most important complications encountered in neonatal units. It has been proposed that phototherapy yields oxidative stress. Therefore, this study was undertaken to survey the levels of antioxidant and oxidative stress in the serum of neonates before and after phototherapy. Methods: This study was performed on thirty-five healthy, late preterm (>35 weeks) and term newborns aged 6-10 days, who underwent phototherapy due to hyperbilirubinemia (>14.00 mg/dL). Infants with a congenital malformation, birth asphyxia, sepsis, signs and symptoms suggestive of severe illness, and receiving phototherapy before recruitment to the study were excluded. Blood samples were taken to determine total serum bilirubin, total antioxidant capacity (TAC) of serum, malondialdehyde (MDA), advanced oxidation protein products (AOPP) as markers of the intensity of oxidative stress and inflammation with photometric methods, reduced and oxidized glutathione (GSH) by HPLC-UV as well as the ratio of them before and after phototherapy. Results: TAC, GSH and bilirubin levels were significantly lower after phototherapy than before it, but reversely about levels of MDA, AOPP and oxidized GSH in addition to the ratio of reduced to oxidized GSH (p<0.05-0.001). AOPP and MDA showed a high negative correlation with bilirubin (respectively R=-0.985 and -0.986, p<0.001)) while vice versa about TAC and GSH (R=0.975 and 0.988, P<0.001). Conclusion: Phototherapy induces oxidative stress and inflammation not only due to the elevation of protein and lipid oxidation but also with reducing of antioxidant markers of serum.