Unique infrared thermographic profiles and altered hypothalamic neurochemistry associated with mortality in endotoxic shock.

Neonatal sepsis results in significant morbidity and mortality, but early detection is clinically challenging. In a neonatal rat model of endotoxic shock, we characterised unique infrared thermographic (IRT) profiles in skin temperature that could identify risk of later mortality. Ten-day old rats were placed in a thermally stable isolette and IRT images of cranial (T), scapula (T) and rump (T) skin temperature were obtained continuously for 8 h following an intraperitoneal injection of lipopolysaccharide (LPS) or saline. LPS resulted in ∼74 % mortality (designated as non-survivors, LPS) between 4.5 and 7.5 h post-injection. LPS and survivors of LPS (LPS) rats displayed hypothermic tendencies with T, T and T decreasing at ∼80-100 min (T) post-injection. Compared to LPS rats, however, the hypothermia of LPS rats occurred slightly earlier (T), was more severe, and failed to recover. The T, T and T of LPS rats fully recovered by 4 h (T) post-injection. In separate rats, hypothalamic microglia and extracellular matrix (ECM) expression at T post-injection were increased in putatively identified LPS rats (but not LPS rats) and negatively correlated with IR temperatures. IRT could be a useful early identifier of infants at risk of death from endotoxic shock, which may be related to early failure of central nervous system (CNS) thermogenic mechanisms mediated by unique hypothalamic changes in inflammatory (microglia) and ECM neurochemistry.