Effects Of Mechanical Ventilation On The Levels Of CC10 Protein In Different Tissues Of Rats

Partâ… Building the rat model of ventilator-induced lung injuryObjective To build an experimental model of ventilator-induced lung injury(VILI)in rats and evaluate the influence of different tidal volume on VILI in rat lung.Methods Thirty normal Wistar rats weighing 200～250g were randomly divided into 3 groups(n=10):group A:control group,spontaneously breathing;group B:tidal volume (V_T)=7ml/kg,ventilation time(t)=4h,respiratory rate(RR)40bpm,FiO₂21%,T_I/E1:2;group C:V_T=40ml/kg,t=4h,RR=40bpm,FIO₂21%,T_I/E1:2.The Model of ventilator-induced lung injury was established.After ventilation,the rats were sacrificed and The left lungs were excised for determination of wet/dry(W/D)lung weight ratio.The right lungs were fixed by 4%formaldehyde solution and stained with hematoxylin and eosin for light microscopic evaluation.Results No substantial changes of lung morphological were observed between group A and group B.But we found that alveolar congestion,hemorrhage and infiltration or aggregation of neutrophils in airspace or vessel wail,thickness of alveolar wall/hyaline membrane formation were observed in group C.The interstitial pulmonary edema and pneumorrhagia were significantly severer in group C than the other two groups.Conclusions Large volume mechanical ventilation results in severe lung injury.It can be concluded that relative larger VT(40 ml/kg)was right volume mechanical ventilation in the establishment of rat model of VILI. Partâ…¡Effects of mechanical ventilation on the levels of CC10 protein in different tissues of ratsObjective To investigate the effects of mechanical ventilation on the levels of CC10 protein in the lung,bronchoalveolar lavage fluid(BALF),and serum of rats.Methods Forty normal Wistar rats weighing 200～250 g were randomly divided into 5 groups(n=8 each).The animals were tracheotomized and intubated,groupâ… :control group,spontaneously breathing;The other groups mechanically ventilated with respiratory rate(RR)40bpm,FIO₂21%,Time(I:E)1:2,groupâ…¡:tidal volume(V_T)7ml/kg,ventilation time(t)2h;groupâ…¢:V_T=7ml/kg,t=4h;groupâ…£:V_T=40ml/kg,t=2h;groupâ…¤: V_T=40ml/kg,t=4h,After ventilation,the rats were sacrificed and the lungs were removed for microscopic examination.The levels of CC10 in the lung,BALF and serum were detected by western blot.The ratio(%)of Clara cells in the bronchiolar epithelium was detected by immunohistochemistry.Results(1)The expression of CC10 in BALF and in lung were lower,in serum were elevated more significantly in groupâ…£,â…¤as compared with that in groupâ… (P＜0.05), but the difference between groupâ…£andâ…¤was not significant(P＞0.05).(2)The levels of CC10 in serum and BALF were related with scores of lung pathology and correlation coefficient were 0.855(P＜0.01),-0.477(P＜0.05)respectively.(3)The ratio(%)of Clara cells in the bronchiolar epithelium in groupâ…¤was lower than that in groupâ… .Conclusions Levels of serum CC10 is significantly relal:ed to the extent of lung injury induced by mechanical ventilation,and it may be the sign of VILI.(2)Mechanical ventilation with high tidal volume and long time decreases production of CC10 in lung tissues and induced lung injury.