Folic acid alleviates jaundice of phenylhydrazine (PHA)-induced neonatal rats by reducing Lys-homocysteinylation of albumin

Neonatal jaundice is a common symptom that occurs in neonates during the first month of their life and is generally divided into physiological and pathological subtypes. In serious cases, pathological neonatal jaundice frequently shows complications including seizures, cerebral palsy, and kernicterus. However, due to the unclear pathogenesis of pathological neonatal jaundice, effective drugs for this disease remain unsatisfied. In the present study, we first estimated the protective effects of folic acid (FA) on phenylhydrazine (PHA) or homocysteine (Hcy)-injected neonatal rats (2-3 days aged). Intriguingly, we found that FA significantly decreased the elevated total bilirubin (TBIL) and direct bilirubin (DBIL) concentration, alanine aminotransferase (ALT), aspartate aminotransferase (AST), and alkaline phosphatase (ALP) activity in PHA- or Hcy-injected rats, indicating that FA improves liver functions. Meanwhile, our results also showed that the plasma Hcy level and N-homocysteinylation (N-Hcy) modification of albumin were significantly elevated in the jaundice rats, which were obviously reversed after FA administration. Furthermore, we identified a novel N-Hcy modification site K