Abstract 1373 Poster Session IV, Tuesday, 5/4 (poster 357)

The homozygous Gunn rat (GR), a Wistar rat deficient in uridine diphosphate glucuronyl-transferase, is the most frequently used animal model in studies of jaundice. A positive correlation between bilirubin concentration in skin extracts and plasma total bilirubin (PBR) has been reported. In this study, we evaluated for the first time the applicability of transcutaneous bilirubinometer measurements (TcB) to the neonatal GR in comparison to PBR measurements by an UB analyzer. TcB were made in pups periodically during the first 5d of life with the Model 101 Minolta/Airshields Jaundice Meter (MTcB) at the occiput, upper and lower back, and only at the lower back with the SpectRx BiliCheck system (STcB) due to its large probe tip. When TcB results by both devices were compared, they displayed parallel profiles of a rapid increase in the first 24h, a gradual increase in the next 6h, and a plateau after 30h. When the TcB was compared with PBR, pre- and post-phototherapy (PT) with light emitting diodes and conventional PT light sources, the following linear regressions (TcB = y; PBR = x) were found: (Table) These results demonstrate that TcB correlates highly with PBR in GR during the first 5 d of life. As has been reported for human neonates, PT decreased the correlations significantly, as well as altered the slopes and intercepts. We conclude that TcB in GR neonates reflect PBR most reliably and consistently at the occiput for MTcB and the lower back for STcB. Furthermore, TcB methodology is a useful tool for the non-invasive monitoring of neonatal Gunn rats.

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