Effects of hypothermia on lung inflammation in a rat model of meconium aspiration syndrome

Purpose: To evaluate the effects of hypothermia treatment on meconium-induced inflammation. Methods: Fifteen rats were instilled with human meconium (MEC, 1.5 mL/kg, 65 mg/mL) intratracheally and ventilated for 3 hours. Eight rats that were ventilated and not instilled with meconium served as a sham group. In MEC-hypothermia group, the body temperature was lowered to 33±0.5°C. Analysis of the blood gases, interleukin (IL)-1β, IL-6, IL-8, and tumor necrosis factor (TNF)-α in bronchoalveolar lavage (BAL) fluid samples, and histological analyses of the lungs were performed. Results: The BAL fluid TNF-α, IL-1β, IL-6 and IL-8 concentrations were significantly higher in the MEC-hypothermia group than in the MEC-normothermia (p < 0.001, p < 0.001, p = 0.001, p < 0.001, respectively) and sham-controlled groups (p < 0.001, p < 0.001, p < 0.001, p < 0.001, respectively). Conclusion: Meconium-induced inflammatory cytokine production is affected by the body temperature control.