ABSTRACT
Objective To investigate the relationship between the expression of MIF mRNA and TNF-α in the lung tissue of rats with acute necrotizing pancreatitis (ANP) and explore their mechanism of action in acute lung injury during the course of ANP. Methods A total of 40 Sprague-Dawley rats were randomly divided into four groups (n = 10 in each group) : the sham operation (SO) group, ANP 3h group, 6h group, 12h group. The model of ANP was induced by retrograde injection of 5% sodium tanrocholate (0. 1 ml/100 g) into the biliary and pancreatic duct. The level of serum amylase was determined;pancreatic and lung tissues were harvested for pathological examination, and wet/dry weight ratios were estimated. Intrapulmonary expression of MIF mRNA was assayed by semi-quantitative RT-PCR. TNF-α in pulmonary homogenate was measured by immunoradiometric assay. Results Serum amylase, wet/dry weight ratios of pancreatic and lung tissues all significantly increased, and pathological injuries aggravated with time in ANP groups. Levels of TNF-α in ANP 3h, 6h, 12h group were (0.69 ± 0. 107) ng/ml, (1.64 ± 0. 10) ng/ml and (0.92 ± 0.11) ng/ml, and expression of MIF mRNA were 1.97±0.09, 2.55±0.23, 3.29±0.26, which were significantly higher than those in control group [(0. 19±0.06)ng/ml, 1.21±0.34, P<0.01]. lntrapulmonary expression of MIF mRNA was positively associated with lung pathological injuries, wet/dry weight ratio, and TNF-α(r = 0. 637, r = 0.684, r = 0.858, P < 0.01). Intrapulmonary levels of TNF-α was positively associated with lung pathological injuries, wet/dry weight ratio (r=0.540, r=0.421, P<0.01). Conclusions MIF mRNA was over- expressed and level of TNF-α was significantly increased in pulmonary tissue in rats with ANP, and this may be one of the mechanisms in the pathogenesis of lung injury in ANP.