Establishment Of Severe Pneumonia Caused By Klebsiella Pneumoniae In SD Rats And The Related Research

Objective To establish severe pneumonia model of SD rats caused by klebsiella pneumoniae and to investigate its diagnostic criteria and pathophysiologic feature, and to observe the variation of the serum cytokine levels and the effect on immune function when infected in order to explain the role of cytokines in severe pneumonia.Method A total of 60 Sprague Dawleg (SD) rats were randomly divided into three groups : model group ( n = 24), observation group ( n = 24), and control group ( n= 12) . Rats in the model group and the observation group were intratracheally instilled with suspension of klebsiella pneumoniae of different dose. Rats in the control group were intratracheally injected with 1 ml saline. On the 2nd, 4th, 6th day after intratracheal instillation, 1/3 rats of each group were killed to determine the concentration of IFN-γ,IL-6 ,TNF-αin blood, the hemodynamics, ABG( arterial blood gas), peripheral hemogram, leukocytes and neutrophils in the BALF(bronchoalveolar lavage fluid) respectively. Lung tissue was stained with HE(hematoxylin and eosin) and observed with the microscope. We randomly selected three to four visual fields from each microtomed section and analyzed the volume density of the erythrocyte, alveolus and the residual lumens of bronchi in the lung parenchyma respectively with the Image-Pro image analysis system.Results 1.The hemodynamic changes of the rats in the model group were significant on the 5th day and the ABG changes appeared on the 4th day. The changes of peripheral hemogram, leukocytes and neutrophils in the BALF, pathology of the lung of the rats in the model group were more obvious than those in the observation group at each time point. As time went by, the changes of hemodynamics, ABG, peripheral hemogram, leukocytes and neutrophils in the BALF and pathology...