Effect of compound hypertonic saline solution on septic rats

Abstract

To study the effect of compound hypertonic saline solution ( HSD ) on sepsis. 133 male Wistar rats were divided into four groups, sham operation group ( n = 15 ), cecal ligation and puncture ( CLP ) group ( n = 45 ), CLP plus normal saline ( NS ) group ( n = 45 ), and CLP plus HSD group ( n = 28 ). A rat model of sepsis was reproduced by CLP, and the rats in sham operation group received celiotomy without ligation and puncture. All rats in four groups received subcutaneous injection of 30 mL/kg 0.9% sodium chloride after laparotomy. The rats in CLP plus NS group and CLP plus HSD group received infusion of 5 mL/kg 0.9% sodium chloride or 7.5% sodium chloride/6% dextran post CLP via jugular vein for 3 hours, with the infusion rate of 0.4 mL×kg(-1)×min(-1). The survival rate of each group was observed 9 hours and 18 hours after laparotomy. Mean arterial pressure ( MAP ) at 0, 9, 18 hours were monitored. Blood specimens were collected from all rats 0, 9 and 18 hours after laparotomy, respectively, for measurement of the plasma levels of tumor necrosis factor-α ( TNF-α), interleukin-1β ( IL-1β ), and procalcitonin ( PCT ). The rats were all sacrificed, and their lung tissues were harvested for the neutrophil count in bronchoalveolar lavage fluid ( BALF ), myeloperoxidase ( MPO ) activity in lung tissue, wet/dry weight ratio ( W/D ) of lung, and pathological changes in lung tissue. There was no death in the sham operation group. The survival rates at 9 hours and 18 hours were 62.2% and 31.1% in the CLP group, 57.8% and 35.6% in the CLP plus NS group, 85.7% and 64.3% in the CLP plus HSD group, and they were all significantly higher compared with those of the CLP group and the CLP plus NS group ( P<0.05 or P<0.01 ). MAP levels in the CLP group and the CLP plus NS group were significantly lower than those in sham operation group, and the plasma levels of TNF-α, IL-1β and PCT were significantly higher compared with those of sham operation group, while there was no difference between CLP group and the CLP plus NS group. MAP and the plasma levels of TNF-α, IL-1β and PCT in the CLP plus HSD group were significantly improved compared with those of the CLP plus NS group at 9 hours and 18 hours [ MAP ( mmHg, 1 mmHg = 0.133 kPa ) at 9 hours: 102±5 vs. 94±6, 18 hours: 90±2 vs. 72±3; TNF-α ( ng/L ) at 9 hours: 284.19±57.18 vs. 329.67±45.79, 18 hours: 263.46±42.58 vs. 349.68±52.40; IL-1β ( ng/L ) at 9 hours: 219.28±39.21 vs. 263.47±32.36, 18 hours: 195.98±39.06 vs. 250.10±41.57; PCT ( μg/L ) at 9 hours: 2.32±0.37 vs. 4.52±0.75, 18 hours: 2.89±0.62 vs. 5.02±0.84; P<0.05 or P<0.01 ]. The ratio of neutrophils in BALF, MPO activity and lung W/D at 18 hours in the CLP group and the CLP plus NS group were significantly higher than those of the sham operation group, while they were all significantly lower in the CLP plus HSD group than those of the CLP group and the CLP plus NS group [ ratio of neutrophils in BALF: 0.094±0.019 vs. 0.148±0.062, 0.151±0.055; MPO ( U/g ): 1.19±0.45 vs. 2.31±0.79, 2.64±0.69; lung W/D ratio: 4.02±0.63 vs. 5.14±0.59, 5.12±0.83, all P<0.05 ]. Under light microscope, no pathobiological changes were found in sham operation group. The lung tissues in the CLP group and the CLP plus NS group showed congestion, edema, infiltrating inflammatory changes, while the inflammatory changes in the lung tissue in the CLP plus HSD group were significantly alleviated. HSD can obviously ameliorate the circulatory failure in septic rats, alleviate immune disturbance and acute lung injury, and improve the survival rate of rats with sepsis.