The effect of phototherapy on sister chromatid exchange with different light density in newborn hyperbilirubinemia.

AIM

Concerns of possible genotoxic effects of hyperbilirubinemia and phototherapy were raised from experimental and observational studies in neonates. The purpose of this study was to assess the effect of hyperbilirubinemia and phototherapy with three different methods on DNA damage by investigating sister chromatid exchange frequency.

MATERIAL AND METHODS

Patients whose gestational ages were >37 weeks and bilirubin levels above phototherapy limits were enrolled into three groups and each group was planned to receive 25 babies. Group 1 received enhanced light-emitting diode phototherapy, group 2 had light-emitting diode phototherapy, and group 3 received conventional phototherapy. Infants with hyperbilirubinemia but did not require phototherapy comprised the control group, which was subdivided into two groups regarding bilirubin levels (10mg/dL). Blood samples were collected before and after phototherapy for sister chromatid exchange frequency and samples were examined by a biologist who was blinded to the study groups.

RESULTS

The mean pre-treatment sister chromatid exchange frequency was 1.41±0.34/cell, post-treatment 2.65±0.68/cell, and 1.61±0.61/cell for the control group (p<0.05). A statistically significant increase in sister chromatid exchange frequency after phototherapy was observed in all three intervention groups (p values: 0.01, 0.01, and 0.008, respectively). When the treatment groups were compared with each other in terms of irradiance, no significant difference was found (p=0.08).

CONCLUSIONS

Phototherapy causes an increase in the frequency of sister chromatid exchange regardless of the irradiance. Phototherapy could have some genotoxic adverse effects on chromosomes; however, further investigations are warranted to enlighten as to whether these effects are permanent or clinically important.