ABSTRACT
Objective To investigate the characteristics of pulmonary function and pathological changes in rats with acute lung injury (ALI) and provide experimental basis for further study on the mechanism of ALI.Methods Twenty five male SD rats were randomly divided into the control group (n =5) and acute lung injury (ALI) group (n =20).Lipopolysaccharide (LPS) (4.5 mg/kg) were injected into the ALI group rats to establish the ALI rat model.The rats in control group were given 150 μl isotonic saline.At 12,24,48,and 72 hours after injury,lung function of the rats were tested by Buxco small animal lung function test system,including the dynamic lung compliance (Cdyn),forced vital capacity (FVC),functional residual gas (FRC),quasi static compliance (Cchord),100th millisecond expiratory volume (FEV100),and airway resistance (RI).In addition,the bronchoalveolar lavage fluid (BALF) was collected for detection of protein level and tumor necrosis factor (TNF-alpha)concentration.At the same time,the changes of lung tissues were recorded,and the pathological changes were observed by HE staining.Results Compared with the control group,Cdyn,FVC,FRC,and FEV100 in ALI group were significantly decreased at each time point after injury (P ＜0.05 or ＜0.01),while the airway resistance (R1) in ALI group was significantly increased at 24 and 48 hours after injury (P ＜ 0.01).There was no significant difference in quasi static compliance (Cchord) between two groups (P ＞ 0.05).The protein level and TNF-alpha concentration of BALF in ALI group were increased significantly (P ＜0.05 or ＜0.01) 12-72 hours after injury (P ＜ 0.01).Compared with the control group,the whole lung was dark red in ALI group 12 hours after injury,and the most serious bleeding occurred in the pulmonary hilum area with single or multiple hemorrhagic foci of different sizes.Multiple punctate and focal bleeding of different sizes were seen on the lung surface,which were radially distributed around the pulmonary hilum.The color of lung tissue was gradually restored to normal at 72 hours after injury.Under the light microscope,pulmonary interstitial edema,inflammatory cell infiltration,pulmonary vascular congestion and focal pulmonary hemorrhage were observed 12 h after injury,showing typical ALl pathological changes.The pathological changes were the most significant at 24 hours and reduced obviously at 72 hours.Conclusions A single intratracheal injection of LPS can induce typical ALI pathological changes.There is a similar trend between the pulmonary function indexes,lung pathology characteristics,and the protein level of BALF and proinflammatory cytokine level,suggesting that the pulmonary function test parameters can provide reference for evaluation of ALI.
ABSTRACT
Objective To investigate the effects of preconditioning with low-concentration hydrogen peroxide ( H2O2 ) on oxidative stress-induced bone marrow mesenchymal stem cells ( BMSCs ) apoptosis and its mecha-nism.Methods Mouse bone marrow mesenchymal stem cells ( BMSCs) were isolated and purified by differential centrifugation, and were treated with 0,200,250,300, 500 μmol/L H2O2 after preincubation with 50 μmol/L H2O2 or control medium.Apoptosis of these cells was measured by flow cytometry, and the expression of phos-phorylated PI3K, Akt and mTOR was analyzed by Western blot; BMSCs were also primed with PI3K inhibitor LY294002 for 30 min, then preincubated with 50 μmol/L H2O2 or control medium for 12 h before treatment with 300 μmol/L H2O2.Expression of apoptosis proteins Bcl-2, Bax, caspaase-3, cleaved-caspase-3 and the key pro-teins of the PI3K/Akt/mTOR pathway were detected by Western blot .Results H2O2 induced BMSCs apoptosis in a dose-dependent manner ,and pretreatment of BMSCs with low concentration of H2O2 significantly decreased H2O2-induced apoptosis of the BMSCs .Western blot results revealed that preconditioning with low-concentration H2O2 re-markably reversed the decrease in Bcl-2, total and phosphorylated PI3K, Akt and mTOR levels, and increased in Bax, cleaved-caspase-3 expression after high-dose H2O2 treatment.Such effects were antagonized by PI3K inhibitor LY294002 .Conclusions Preincubation with low-concentration H2O2 may indnce resistance of BMSC to oxidative stress, and such effect may be mediated by inhibition of pro-apoptotic proteins and activation of the PI 3K/Akt/mTOR pathway .
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Objective To explore the enhancing effect of monoclonal antibody coated with anti-human CD3 and CD28 on acti-vation and transformation of peripheral blood mononuclear cell (PBMC)in vitro.Methods Human peripheral blood mononuclear cells were separated.Cells was cultured in vitro,and determined by flow cytometry.The solid phase with CD3 and CD28 antibody was coated and added in.The mature CIK cells were obtained after 12 days culturing.Results The CD4 + cells was lower in group C than those in group A(P <0.05).The CD8 + cells was higher in group C than that in group A and B(P <0.05).There was signifi-cant difference of T4/T8 between group C and group A and B(P <0.05 ).There was significant difference of NK cells between group B and group C(P <0.05).The CD25 + cells was lower in group C than that in group A (P <0.01).Conclusion CD3 antibody solid coated combined with CD28 antibody added to the suspension has more strong activation than both CD3 antibody and CD28 antibody solid coating on peripheral blood mononuclear cell.