Effects Of Penehychdine On The Expression Of AQP1, AQP5 After Acute Lung Injury Induced By LPS

Objective The effects and mechanism of penehychdine on acute lung injury induced by LPS were investigated by detecting the SOD activity,MDA content, and the AQP1, AQP5 expression as well as the pathological change in lung .Methods Seventy-five SD rats, 180-200g, were randomly divided into five groups after one week'free diet (n=15): control group (group C), ALI group, penehyclidine group (low dose (group PL), middle dose (group PM), high dose (group PH)). The ALI model was established by intravenous injection LPS (5mg/kg), group PL, PM, PH got PHCD 0.05mg/kg, 0.15mg/kg, 0.45mg/kg intraperitoneal injection respectively 10 minutes after LPS injection. Group C got the same volume saline intraperitoneal and intravenous injection. The animals were decapitated at 2, 6 and 12h after operation (n=5 at each time point in each group). The pulmonary permeability index (PPI) was calculated by the ratio of plasma protein content and protein content in bronchial lung lavage fluid (BALF) measured from the left lung, the wet/dry (W/D) ratio as well as the SOD activity, MDA content were measured from the right side lobe, and the rest tissue of right lobe was for electron and light microscopy observation, the expression of AQP1, AQP5 was detected by immunohistochemistry. The trial datus were analyzed with ANOVA by SPSS 13.0.Results(1) The W/D ratio, PPI, SOD activity and MDA content in the lung: There was no significant change in group C (P> 0.05). Compared with group C, the W/D ratio, PPI, MDA level increased and SOD activity decreased at 2h and got more obvious at 12h (P<0.05). Compared with group ALI, the W/D ratio, PPI, MDA level decreased and SOD activity increased in group P (P<0.05). Compared with group PL, there were significant difference in corresponding data in group PM and group PH (P<0.05), but no significant difference could be found between group PM and group PH. (P>0.05).(2) The AQP1, AQP5 expression in the lung: The brown particles which represented AQP1 were discovered in the alveolar capillary endothelial cells and the typeâ…¡alveolar epithelial cells, and AQP5 in the typeâ… alveolar epithelial cells in all group, The AQP1 and AQP5 expression showed no significant changes in group C at 2h, 6h and 12h (P> 0.05). Compared with P group, the AQP1 and AQP5 expression declined with time in group ALI(P<0.05). The expression in group P which was lower than in group C and higher than in group ALI increased with time(P<0.05).The AQP1 expression showed statistical significance at 6h compared at 2h in ALI group and in P group, while AQP5 showed statistical significance at 12h compared at 2h in ALI group as well as in P group(P<0.05); the AQP1 expression in group PH was higher than that in group PL and PM at the same time(P<0.05), but there was no statistical significance between group PL and PM(P>0.05). Meanwhile compared with , the AQP5 expression in group PM and PH was higher than in group PL at the same time(P<0.05), but there was no statistical significance between group PM and PH(P>0.05).(3) Pathological observation of lung tissue:Gross observation: Group C had normal lung structure and appeared pink; In group ALI, the lung was swelling, punctuate or massive lesions could be found on the surface, and white or faint red foam-like liquid spilled form the cross-section; the penehyclidine groups were alleviated in different degrees.Light microscope: There was no change in group C; in group ALI, the alveolar wall was damaged seriously, the pulmonary interstitial and alveolar epithelial cells became edema, polymorphonuclear leukocyte infiltrated, and the red blood cells, inflammatory cells could be found in alveolar cavities; but it was quietly alleviated in group PH.Electron microscopy: The typeâ… alveolar epithelial cells in group ALI, which the border was unclear, the membrane continuity was interrupted, and the cytoplasm got cavitated, nuclear became swelled, dissolved even disappeared. In the typeâ…¡alveolar epithelial cells, the lamellar body could be found, while cytoplasm cavitation and capillary endothelial swelling were damaged seriously. In the penehyclidine groups, the typeâ… alveolar epithelial cells were swelling, while the cell contour were still obvious, and the basic structure was integrate; in the typeâ…¡alveolar epithelial cells ,the lamellar body increased slightly, capillary endothelial were swelling mild.Conclusion(1)The W/D ratio, PPI, and MDA content increased while the SOD activity, AQP1 and AQP5 expression decreased with time after ALI induced by LPS injection, parallel to the pathological changes in lung tissue, and had not yet improved at 12h.(2)In the P group, the W/D ratio, PPI, MDA content decreased and the SOD activity, AQP1, AQP5 expression increased with time, the same to the pathological changes in lung tissue, which changed more obviously at 12h. There was no significant difference between PH and PM group, which suggested that the PH group was close to the best therapeutic effect.(3)The AQP1 down-regulating was faster than AQP5 after LPS injected, and up-regulating was faster than AQP5 after PHCD injection, which suggested that the AQP1 was more sensitive to stimulate. It maybe owing to the different structures ,anatomic distributions, physiology functions and different regulation pathways.