Study On The High Permeabilized Opening Of Lung Mitochondrial Permeability Transition Pore And Subsequent Effects On Mice Induced By Beryllium Sulfate

Objective:To observe the influence and subsequent effects of mitochondrial permeabilitytransition pore(mPTP) induced by beryllium sulfate (BeSO4) on mice via animal vivoexperiment, and enrich the mechanism about pulmonary toxicity induced by BeSO4.Method:Thirty-six six-week-old male Kunming mice were randomly divided into threegroups with per group12. The normal control group was administered with sterilesaline solution by intraperitoneal injection according to0.1ml/10g body weight; thetwo experimental groups were administered with sterile saline solution of berylliumsulfate (1mg/kg,2mg/kg) by peritoneal injection respectively, every other day for onemonth. The general instance about growth, development and activity of mice wereobserved during the experiment. After the last injection, all mice were sacrificed byneck breaking method, the integral lung was dislodged rapidly. Histopathologicalchanges of lung were observed under light microscope. The mitochondrion washomogenated to isolate lung mitochondria by differential centrifugation. The ReactiveOxygen Species (ROS) and mitochondrial transmembrane potential (Δψm) weredetected by fluorospectrophotometry. The opening extent of mPTP was monitored byspectrophotography. And the expression of some apoptotic proteins, such ascytochrome C, Bax, Bcl-2were detected by Western Blot.Results:1. During the experimental period, the diet and activiety of mice in control groupwere normal, but the mice in BeSO4groups were less active. After the first week ofexperiment, the weight of mice in2mg/kg BeSO4groups were lower than the normalcontrol group (P＜0.05). After the second, third and forth week of experiment, theweight of mice in1mg/kg and2mg/kg BeSO4groups were both lower than the control group, and the difference were significant repectively(P＜0.05).2. After histopathologic observation, the structure of lung were normal in controlgroup. The experimental group of1mg/kg presented hyperemia, hemorrhage, slightalveolar inflammatory corpuscle, peribronchitis, interstitial pneumonia and lobularpneumonia. In lung tissue of2mg/kg experimental group, it was observedbronchiectasic hemorrhage, bronchial alveolar ectasia, severe bronchialinflammatory exudates, interstitial pneumonia, lobular pneumonia and syzygiapneumonia.3. The contents of ROS, swelling degree of mPTP, expression of Cytochrome Cof lung cytoplasm and pro-apoptotic protein Bax were increased with the dose ofBeSO4(P<0.01), the difference of three groups were significant respectively (P<0.05);Compared with the normal control group, mitochondrial transmembrane potential(Δψm), expression of anti-apoptotic protein Bcl-2and the value of Bcl-2/Bax werelower in BeSO4groups (P<0.01), and they decreased with the dose of BeSO4in allexposure (P<0.01).Conclusion:1.BeSO4can induce lung histopathological changes mainly with inflammationand apparent pulmonary toxicity in mice by intraperitoneal injection.2.BeSO4can induce the high permeabilized opening of mitochondrialpermeability transition pore of lung by intraperitoneal injection, so that themitochondrial Δψm were reduced, Cyt-C were released to cytoplasm, then theexpression of pro-apoptotic protein Bax was increased, but expression ofanti-apoptotic protein Bcl-2was reduced. It suggests that the high permeabilizedopening of mPTP is closely linked to the pulmonary toxicity induced by BeSO4.