Effect Of Naloxone On Acute Respiratory Distress Syndrome Induced By Oleic Acid In Rats

Purose:To observe the effect of naloxone on acute respiratory distress syndro me induced by oleic acid in rats.Methods:30healthy SD rats were randomly divided into three groups,Control group,ARDS group and Naloxone-treated group. Control group:injected normal saline (NS,4.0ml/kg). ARDS group:injected oleic acid (0.1ml/kg) and NS (4.0ml kg). Naloxone treatment group:injected oleic acid (0.1ml kg) a nd naloxone (1.0mg/kg,diluted in4.0ml/kg of NS).3hours later, collect an d centrifugate blood,and maintain it in refrigerator with-40degrees for frozen storage; take the wet weight of left lung lobe,drying it in70degrees and tak e the dry weight; Place the upper lobe of right lung in refrigerator with-70degrees for frozen s torage, using4%formalin fix medium lobe, fix lower lobe with PBS and3%of glutaraldehyde; determine the plasma β-EP and serum ANP and BNP by EL ISA;determine the lung tissue NKA by biochemical method; determine the nuclear transcription factors-kB by immunohistochemical staini ng method;preparation of specimens of electron microscope and light microscop e to observe organizational change of lung.Results:1.Comparing with the control group, the wet/dry weight value of lung has been elevated in ARDS model and naloxone group, the wet/dry weight value of naloxone group has been descended than ARDS model group.2. Comparing with the control group, the β-EP、ANP and BNP level in plasma of ARDS model group increased significantly(p<0.01); the nuclear transcription factors-kB nuclear transfer in ARDS model group increased significantly(p<0.01); the level of NKA in lung tissue declined significantly (p<0.01); comparing with the ARDS model group,every indicators in naloxone group had significantly difference (p <0.01).3. The correlation between indicators: The β-EP in plasma, levels of ANP and BNP in serum, the positive rates of nuclear transcription of NK-kB in lung tissue, the level of NKA have relevance with the wet/dry weight value(p<0.01); the level of β-EP、ANP、 BNP have relevance with the positive rates of nuclear transcription of NK-kB in lung tissue (p<0.0).4. The observational results in pathology:Microscopic results: The structures in control group is normal, without effusion or edema; in ARDS model group the alveoli is atrophy,in alveolar lumen-can see effusion, neutrophils and foam cells,parts of the alveolar can see transparent membrane, pulmonary interstitial edema, thickening, neutrophil infiltration. Surrounding the capillary can see cuff-form edema and thickening, cuff edema can be seen around the blood vessels; the pathological change in Naloxone group is slight.Electron microscopy results: oleic acid groups: The structures in control group is normal; swelling and necrosis can be seen in Type Ⅰ alveolar epithelial cells and endothelial cells, degeneration, destruction, evacuating phenomenon in lamellar body of Type Ⅱ alveolar epithelial cells,uneven size of vacuoles, on alveolar surface can see covering a layer of the funicular material, interval between alveolar has been widen, inflammatory cells can be seen in the alveolar cavity. These changes lighter in naloxone group.Immunohistochemical staining results: NK-kB express positive cells are manipulus in control group, NK-kB express positive cells are increased in the cells of tracheal mucosa epithelium and lung epithelial cells in ARDS model group, the distribution of the cells is similar with the ARDS model group, but the NF-kB express positive cells in naloxone group is reduced.Conclusions:1.β-EP in plasma, ANP and BNP in serum, NF-kB express positive rates, levels of NKA are correlated with the lung wet/dry weight ratio in early ARDS, which shows that the above indicators can reflect the edema degree of lung tissue.2. β-EP in plasma, serum ANP and BNP levels is correlated with the lung tissue NF-kB, may affect the lung inflammation.3.Naloxone may inhibit plasma p-EP, increase serum ANP and BNP, block the lung tissue NF-kB activation, improve the activity of NKA, reduce pulmonary interstitial and alveolar edema, lung tissue necrosis.