Reproduction of acute lung injury model induced by paraquat in piglet

Abstract

To reproduce acute lung injury (ALI) model induced by paraquat (PQ) in piglet. Ten healthy female piglets were divided into control group (n=4) and the experimental group (n=6) in accordance with the random number table. The experimental group was given intraperitoneal injection of 20% PQ (20 mL) to reproduce the model of ALI, while the control group was given the same amount of normal saline. All piglets were dynamically monitored with pulse-indicated continuous cardiac output (PiCCO) for heart rate (HR), mean arterial pressure (MAP), extravascular lung water index (EVLWI) and pulmonary vascular permeability index (PVPI). Changes in arterial blood pH, oxygen partial pressure (PaO₂), partial pressure of carbon dioxide (PaCO₂), oxygenation index (PaO₂/FiO₂), peak inspiratory pressure (PIP) and platform of the airway pressure (Pplat) were recorded until the PaO2/FiO₂ ≤ 300 mmHg. Pathological changes in lung tissue under microscopy were observed. Model of ALI induced by PQ was successfully reproduced in the experimental group in 5 piglets. The average time of successful reproduction was (4.5 ± 0.2) hours. The HR, MAP, EVLWI, PVPI, PIP and Pplat of the experimental group were increased gradually after PQ intraperitoneal injection, and all indices were significantly higher than those in control group when the model was successfully reproduced (HR: 132.0 ± 6.9 bpm vs. 113.0 ± 3.4 bpm, t=-21.632, P=0.000; MAP: 114.0 ± 6.0 mmHg vs. 98.0 ± 3.5 mmHg, t=-18.217, P=0.000; EVLWI: 19.2 ± 2.8 mL/kg vs. 12.5 ± 1.2 mL/kg, t=-76.283, P=0.000; PVPI: 5.9 ± 1.3 vs. 3.1 ± 0.4, t=-31.879, P=0.000; PIP: 25.4 ± 2.5 cmH₂O vs. 18.6 ± 1.5 cmH₂O, t=-77.421, P=0.000; Pplat: 19.6 ± 2.2 cmH₂O vs. 13.5 ± 1.7 cmH₂O, t=-69.452, P=0.000). The pH value, PaO₂ and PaO₂/FiO₂ declined gradually while the PaCO₂ elevated gradually in experimental group after PQ intraperitoneal injection, the differences between the two groups were statistically significant (pH value: 7.35 ± 0.04 vs. 7.43 ± 0.05, t=9.108, P=0.000; PaO₂: 82.0 ± 7.4 mmHg vs. 172.0 ± 11.6 mmHg, t=102.470, P=0.000; PaCO₂: 44.0 ± 4.0 mmHg vs. 35.0 ± 2.0 mmHg, t=-10.217, P=0.000; PaO₂/FiO₂: 273.0 ± 14.8 mmHg vs. 573.0 ± 22.5 mmHg, t=341.565, P=0.000). Obvious damage of pulmonary tissue was shown when the model was reproduced. By intraperitoneal injections of 20% PQ 20 mL, a stable PQ-induced ALI model can be reproduced in piglets.