Differences in organ dysfunction between gram-positive and gram-negative bacteria-induced sepsis in rats / 中华麻醉学杂志

ABSTRACT

Objective:To evaluate the differences in organ dysfunction between gram-positive and gram-negative bacteria-induced sepsis in rats.Methods:Fifty-two adult male Sprague-Dawley rats, weighing 340-380 g, aged 15-18 weeks, were divided into 3 groups using a random number table method: control group (C group, n=12), G - bacteria group ( n=20), and G + bacteria group ( n=20). The G + and G - septic models were developed by intraperitoneal injection of inactivated Staphylococcus aureus and Escherichia coli suspension in G + and G - bacteria groups, respectively.The survival status within 36 h after injection of inactivated bacteria was recorded.Mean arterial pressure (MAP), platelet count (Plt), oxygenation index (OI) and serum concentrations of tumor necrosis factor α (TNF-α), cardiac troponin T (cTnT), total bilirubin (TBIL), creatinine (Cr), neuron-specific enolase (NSE) and lactic acid (Lac) were measured at 6, 12, 24 and 36 h after injection of inactivated bacteria.Fear conditioning test and open field test were performed at 12 and 36 h after injection of inactivated bacteria.The apoptosis rate of neurons in hippocampal CA1 area was measured by TUNEL, and the permeability of blood-brain barrier was measured by Evans blue method.The histopathological changes of lung, heart, kidney and brain tissues were examined at 36 h after injection of inactivated bacteria. Results:Compared with C group, the number of crossing grids and percentage of time spent freezing were significantly decreased, the apoptosis rate of neurons and permeability of blood-brain barrier were increased, and the survival rate was decreased in G - bacteria group and G + bacteria group ( P<0.05); the serum TNF-α concentration was significantly increased in G + bacteria group, and the serum cocentration of OI was significantly decreased, and the serum concentrations of cTnT, Cr, TNF-α and Lac were increased in G - bacteria group at 6 h after injection of inactivated bacteria ( P<0.05); the serum concentrations of cTnT, Cr, NSE, TNF-α and Lac in G + bacteria group and serum concentrations of cTnT, Cr, TNF-α and Lac in G - bacteria group were increased, and the OI, MAP and Plt were decreased at 12 h after injection of inactivated bacteria in both groups ( P<0.05); the serum concentrations of cTnT, TBIL, Cr, NSE, TNF-α and Lac were increased, and OI, MAP and Plt were decreased at 24 and 36 h after injection of inactivated bacteria in G + bacteria group and G - bacteria group ( P<0.05). Compared with G + bacteria group, the serum concentrations of TNF-α and cTnT and apoptosis rate of neurons were significantly decreased at 12 h after injection ( P<0.05); the serum concentrations of TNF-α and Lac were significantly increased, the serum concentrations of cTnT, OI, MAP and Plt were decreased at 24 h after injection of inactivated bacteria ( P<0.05); the serum concentrations of Cr, NSE, TNF-α and Lac were significantly increased, OI, MAP and Plt were decreased, and the percentage of time spent freezing, apoptosis rate of neurons and permeability of blood-brain barrier were increased at 36 h after injection of inactivated bacteria in G - bacteria group ( P<0.05). Conclusions:Early respiratory dysfunction and multiple organ failure often occur in G - bacteria sepsis, while G + bacteria sepsis is more likely to cause early circulatory and neurological dysfunction, and G - sepsis presents with more serious organ damage and high fatality rate as the disease progresses.