| Objective:To observe the lung tissue damage of SD rats by beryllium sulfate(BeSO4)-induced via non-exposed intratracheal instillation, and application of sodiumhydrosulfide [NaHS, an donor of endogenous hydrogen sulfide (H2S)] and DL-propargylglycine [PPG, inhibitor of cystathionine γ-lyase(CSE), endogenous hydrogensulfide synthesizing enzyme of lung tissue] intervention, clarify the effects ofendogenous hydrogen sulfide on BeSO4-induced lung injury in rats and explore itsmechanism.Method:Forty eight specific pathogen free male SD rats were randomly divided into thecontrol group, the BeSO4group, the BeSO4+NaHS group and the BeSO4+PPG group(n=12). The control group were treated non-exposed intratracheal instillation (0.001ml/g·BW) of sterile saline,30minutes later, intraperitoneal injection(0.01ml/g·BW) ofsterile saline, others were administrated intratracheal instillation of12mg/kg BeSO4,30minutes later, sterile saline,14μmol/L NaHS and37.5mg/kg PPG were injectedintraperitoneal respectively. The activity, diet, mental state, respiration and growthwere observed, two weeks weighed once. After7weeks, animals were killed bycarotid bloodletting for the collection of blood, preparation of plasma, the content ofendogenous H2S in plasma was measured by deproteinization method. The lung waspromptly removed and weighed. Ligation of the right mainstem bronchus, the leftlung lobe was used for bronchoalveolar lavage(BAL), the bronchoalveolar lavagefluid (BALF) was collected for inflammatory cell count. The right lung tissue isdivided into three parts. The right upper lung was fixed and the pathomorphologicaland ultrastructure changes of lung tissue were observed. The right middle lung was homogenized, the content of reactive oxygen species (ROS), malondialdehyde (MDA)and endogenous H2S in lung tissue, the activity of superoxide dismutase (SOD) andglutathione peroxidase (GPx) were detected. extraction of total RNA and protein fromright lower lung tissue, the CSE, SOD and GPx mRNA expression were detected byRT-PCR, the CSE, Phosphatidylinositol-3-kinase(PI3K), total-Akt(t-Akt), phospho-Akt(p-Akt), p53, Bax and Bcl-2protein expression were detected by Western Blot.Results:1. After exposure to BeSO4, the activity and diet of rats in BeSO4group andBeSO4+PPG group significantly reduced, listlessness, some rats rapid breathing in thelate; the activity diet, mental state and respiration of rats in control group andBeSO4+NaHS group were normal. Compared with the control group, the body weightof rats in BeSO4group and BeSO4+PPG group slow growth, some rats weight down;at the5weeks and7weeks, the body weight of rats in BeSO4+PPG group reduced(allP<0.05); at the7weeks, the body weight of rats in BeSO4+PPG group lower thanBeSO4+NaHS group(P<0.05). After the animals were sacrificed, the lung congestionswollen, hard and white spots were observed in BeSO4group and BeSO4+PPG grouprats.2. Histopathologic observation: the control group showed relatively normalhistological structure of lung; the BeSO4group and BeSO4+PPG group were showeda significant damaged of lung tissue, with extensive inflammatory cell infiltration,fibrous tissue and macrophage proliferation, even necrosis, and the ultrastructural oflung tissue was significantly damaged, nuclear condensation, pulmonary fibrosis, thestructural change of blood-air barrier.3. Compared with the control group, in the BeSO4group, BeSO4+NaHS group andBeSO4+PPG group, the lung coefficient, the contents of ROS and MDA in lung tissue,the number of inflammatory cells in BALF were significantly increased (all P<0.05),the contents of endogenous H2S in the plasma and lung tissue, the activity of SOD andGPx were decreased (all P<0.05), the mRNA expression of CSE, SOD, GPx, and theprotein expression of CSE, PI3K, p-Akt, Bcl-2were down-regulated(all P<0.05), butthe protein expression of p53and Bax were up-regulated(all P<0.05); the change of various indicators were improved by NaHS(P<0.05); the lung injury of rats wasalleviated by NaHS; but the lung injury of rats was exacerbated by PPG(P<0.05).Conclusion:1. BeSO4can induce lung tissue oxidative damage, inflammation and apoptosisin SD rats by intratracheal instillation.2. Endogenous hydrogen sulfide protects against BeSO4-induced lung injury inSD rats.3. The protective effects of endogenous hydrogen sulfide on BeSO4-induced lunginjury of rats depend on the PI3K/Akt signaling pathway activation. |
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