Albumin administration protects against bilirubin-induced auditory brainstem dysfunction in Gunn rat pups

Background Free bilirubin (Bf), the unbound fraction of unconjugated bilirubin (UCB), can induce neurotoxicity, including impairment of the auditory system, which can be assessed by brainstem auditory evoked potentials (BAEPs). We hypothesized that albumin might reduce the risk of neurotoxicity by decreasing Bf and its translocation into the brain. AimTo determine the effects of albumin on BAEPs and brain bilirubin content in two Gunn rat pup models of acute hyperbilirubinemia. MethodsWe used Gunn rat pups, which have a deficiency of the bilirubin-conjugating enzyme UGT1A1. We induced haemolysis by injection of phenylhydrazine (phz) into 14-days old pups. Subsequently, pups were treated with either i.p. human serum albumin (HSA; 2.5g/kg; n=8) or saline (control, n=8). We induced acute neurotoxicity by injecting 16-days old pups with sulphadimethoxine (sulpha) and treated them with either HSA (n=9) or saline (control, n=10). To assess bilirubin neurotoxicity, we used the validated BAEP method and compared relevant parameters; i.e. peak latency values and interwave interval (IWI) between peak I and peak II, a marker of acute neurotoxicity. ResultsPhz and sulpha significantly increased IWI I-II by 26% and 29% (P