A comparison of neonatal and adult multiorgan failure in a rat model

Abstract

Background/Purpose: To establish a neonatal animal model of multiorgan failure (MOF) for the histological study of the sequence and severity of neonatal MOF in comparison to a model of adult MOF.Methods: Neonatal and adult Sprague-Dawley rats received a single intraperitoneal injection of the inflammatory agent Zymosan. Rats were weighed; randomly killed on days 1 through 6; and heart, lung, liver, kidney, spleen, and ileocecum harvested for histological examination.Results: Neonatal animals receiving Zymosan showed a significant increase in total body weight not seen in adults. The sequence and severity of MOF-induced organ damage were strikingly different in adult and neonatal animals. Mild lung damage was seen as early as day 1 in adult rats receiving Zymosan. This progressed to moderate damage by day 2 and severe damage by day 6. Lungs of neonatal rats receiving Zymosan showed only mild damage by day 4, which had progressed no further by day 6. Mortality rate was not significantly different between adult and neonatal animals receiving Zymosan.Conclusions: Zymosan can be used in a neonatal animal model to incite MOF. In the neonatal animal model of MOF there is (1) substantial early capillary leak as shown by increased body weight; (2) a unique progression of organ involvement—liver, kidney, lung compared with adult animals with MOF—lung, liver, kidney; and (3) relative sparing of the lung from injury. These findings are consistent with previous clinical observations of a difference in neonatal and adult MOF.