The effects of bilirubin and phototherapy on neonatal thiol-disulfide homeostasis

Abstract

Objective: To determinate the effects of bilirubin and phototherapy on oxidative stress in newborns. Study Design: A case-control study. Place and Duration of Study: Third level Newborn Intensive Care Unit, Ankara Etlik Zubeyde Hanim Women's Health Teaching and Research Hospital, Turkey, from May to August 2017. Methodology: Blood samples of 62 term newborns were grouped as control, before and after phototherapy. Total and native thiol, disulfide and ischemia modified albumin values in expressed blood samples were measured. Disulfide-native thiol ratio, disulfide-total thiol ratio and native thiol-total thiol ratio values were computed. Results: Bilirubin levels were positively correlated with native and total thiol levels and negatively correlated with ischemia modified albumin levels (r=0.409 p= 0.001, r= 0.328 p<0.009, r=-0.503 p<0.001). Native and total thiol levels of the control group were lower (p<0.001) and ischemia modified albumin levels were higher than those before and after phototherapy (p<0.001). In jaundiced newborns, native and total thiol values reduced after phototherapy, while IMA levels increased (p=0.001, p<0.001, p<0.001). Conclusion: Bilirubin showed antioxidant effect without increasing oxidative stress. Oxidative stress increased after phototherapy. This result was associated with decrease in bilirubin rather than oxidative effect of phototherapy.