RESUMEN
OBJECTIVES: Methamphetamine (MA) abuse evokes pulmonary toxicity. The aim of our study is to investigate if autophagy is induced by MA and if autophagy-initiated apoptosis in alveolar epithelial cells is involved in MA-induced chronic pulmonary toxicity. MATERIALS AND METHODS: The rats in Control group and MA group were tested by Doppler and HE staining. The alveolar epithelial cells were treated with MA, following by western blot, RT-PCR and immunofluorescence assay. RESULTS: Chronic exposure to MA resulted in lower growth ratio of weight and in higher heart rate and peak blood flow velocity of the main pulmonary artery of rats. MA induced infiltration of inflammatory cells in lungs, more compact lung parenchyma, thickened alveolar septum and reduction in the number of alveolar sacs. In alveolar epithelial cells, the autophagy marker LC3 and per cent of cells containing LC3-positive autophagosome were significantly increased. MA dose dependently suppressed the phosphorylation of mTOR to inactivate mTOR, elicited autophagy regulatory proteins LC3 and Beclin-1, accelerated the transformation from LC3 I to LC3 II and initiated apoptosis by decreasing Bcl-2 and increasing Bax, Bax/Bcl-2 and cleaved Caspase 3. The above results suggest that sustained autophagy was induced by long-term exposure to MA and that the increased Beclin-1 autophagy initiated apoptosis in alveolar epithelial cells. CONCLUSIONS: Concurrence of autophagy with apoptosis in alveolar epithelial cells contributes to chronic pulmonary toxicity induced by MA.
Asunto(s)
Células Epiteliales Alveolares/efectos de los fármacos , Apoptosis/efectos de los fármacos , Autofagia/efectos de los fármacos , Pulmón/efectos de los fármacos , Metanfetamina/farmacología , Neumonía/inducido químicamente , Células A549 , Células Epiteliales Alveolares/metabolismo , Animales , Beclina-1/metabolismo , Caspasa 3/metabolismo , Línea Celular Tumoral , Humanos , Pulmón/metabolismo , Masculino , Proteínas Asociadas a Microtúbulos/metabolismo , Neumonía/metabolismo , Ratas , Ratas Wistar , Proteína X Asociada a bcl-2/metabolismoRESUMEN
The imbalance between oxidative stress and antioxidant defense is important in the pathogenesis of lung diseases. Nuclear factor erythroid2related factor 2 (Nrf2) is a key transcriptional factor that regulates the antioxidant response. The purpose of the present study was to investigate whether Nrf2mediated antioxidative defense is involved in methamphetamine (MA)induced lung injury in rats. Following establishment of chronic MA toxicity in rats, Doppler ultrasonic detection was used to measure the changes of physiological indexes, followed by hematoxylin and eosin staining, ELISA and western blot analysis. MA was demonstrated to increase the heart rate and peak blood flow velocity of pulmonary arterial valves and to decrease the survival rate of rats, and resulted in lung injury characterized by perivascular exudates, airspace edema, slight hemorrhage and inflammatory cell infiltration. MA significantly inhibited the expression of nuclear Nrf2 protein and its target genes (glutamatecysteine ligase catalytic subunit C and heme oxygenase1), and dosedependently reduced glutathione (GSH) levels and the ratio of GSH/oxidized glutathione, accompanied by increases in reactive oxygen species (ROS) levels in rat lungs. Linear regression analysis revealed that there was a positive correlation between lung ROS level and lung injury indexes. These findings suggested that chronic exposure to MA led to lung injury by suppression of Nrf2mediated antioxidative defense, suggesting that Nrf2 may be an important therapeutic target for MAinduced chronic lung toxicity.
Asunto(s)
Antioxidantes/metabolismo , Lesión Pulmonar/patología , Pulmón/efectos de los fármacos , Metanfetamina/toxicidad , Factor 2 Relacionado con NF-E2/metabolismo , Animales , Velocidad del Flujo Sanguíneo/efectos de los fármacos , Ensayo de Inmunoadsorción Enzimática , Glutamato-Cisteína Ligasa/genética , Glutamato-Cisteína Ligasa/metabolismo , Glutatión/análisis , Frecuencia Cardíaca/efectos de los fármacos , Hemo-Oxigenasa 1/genética , Hemo-Oxigenasa 1/metabolismo , Pulmón/diagnóstico por imagen , Lesión Pulmonar/inducido químicamente , Lesión Pulmonar/mortalidad , Masculino , Factor 2 Relacionado con NF-E2/genética , Estrés Oxidativo/efectos de los fármacos , Arteria Pulmonar/efectos de los fármacos , Arteria Pulmonar/fisiología , Ratas , Ratas Wistar , Especies Reactivas de Oxígeno/análisis , Especies Reactivas de Oxígeno/metabolismo , Tasa de Supervivencia , Ultrasonografía DopplerRESUMEN
Methamphetamine (MA) leads to cardiac and pulmonary toxicity expressed as increases in inflammatory responses and oxidative stress. However, some interactions may exist between oxidative stress and endoplasmic reticulum stress (ERS). The current study is designed to investigate if both oxidative stress and ERS are involved in MA-induced chronic pulmonary toxicity and if antioxidant tertiary butylhydroquinone (TBHQ) alleviated ERS-apoptosis and oxidative stress by PERK-Nrf2 crosstalk. In this study, the rats were randomly divided into control group, MA-treated group (MA), and MA plus TBHQ-treated group (MA + TBHQ). Chronic exposure to MA resulted in slower growth of weight and pulmonary toxicity of the rats by increasing the pulmonary arterial pressure, promoting the hypertrophy of right ventricle and the remodeling of pulmonary arteries. MA inhibited the Nrf2-mediated antioxidative stress by downregulation of Nrf2, GCS, and HO-1 and upregulation of SOD2. MA increased GRP78 to induce ERS. Overexpression and phosphorylation of PERK rapidly phosphorylated eIF2α, increased ATF4, CHOP, bax, caspase 3, and caspase 12, and decreased bcl-2. These changes can be reversed by antioxidant TBHQ through upregulating expression of Nrf2. The above results indicated that TBHQ can alleviate MA-induced oxidative stress which can accelerate ERS to initiate PERK-dependent apoptosis and that PERK/Nrf2 is likely to be the key crosstalk between oxidative stress and ERS in MA-induced chronic pulmonary toxicity.
Asunto(s)
Apoptosis/efectos de los fármacos , Estrés del Retículo Endoplásmico/efectos de los fármacos , Hidroquinonas/toxicidad , Pulmón/patología , Factor 2 Relacionado con NF-E2/metabolismo , Estrés Oxidativo/efectos de los fármacos , Animales , Antioxidantes/farmacología , Hemodinámica/efectos de los fármacos , Pulmón/efectos de los fármacos , Masculino , Metanfetamina , Ratas Wistar , Transducción de Señal/efectos de los fármacos , Remodelación Vascular/efectos de los fármacos , eIF-2 Quinasa/metabolismoRESUMEN
Methamphetamine (MA) leads to multiple organs lesions and apoptosis. The aim of this study is to investigate if endoplasmic reticulum stress (ERS) - initiated apoptosis is involved in the chronic pulmonary injury induced by MA. In this study, rats were divided into a control group, methamphetamine 5mg/kg group and methamphetamine 10mg/kg group. This study found that the protein level of GRP78 is higher in M10 group than in control group. PERK signaling and the relevant apoptosis factors were also activated. Morphological measurements showed that protein BAX and CHOP accumulated in the alveolar epithelium and the alveolar walls with epithelium were damaged and that the number of pulmonary alveoli decreased. The findings showed that ERS and PERK pathway are activated and eventually lead to apoptosis. Severe ERS mediated the apoptosis of alveolar epithelium cells as well as decreasing numbers of pulmonary alveoli.
Asunto(s)
Apoptosis/efectos de los fármacos , Estrés del Retículo Endoplásmico/efectos de los fármacos , Lesión Pulmonar/inducido químicamente , Lesión Pulmonar/metabolismo , Metanfetamina/toxicidad , Animales , Chaperón BiP del Retículo Endoplásmico , Factor 2 Eucariótico de Iniciación/metabolismo , Proteínas de Choque Térmico/metabolismo , Pulmón/efectos de los fármacos , Pulmón/metabolismo , Pulmón/patología , Masculino , Ratas Wistar , Factor de Transcripción CHOP/metabolismo , eIF-2 Quinasa/metabolismoRESUMEN
Methamphetamine (MA) abuse is a major public health and safety concern throughout the world and a growing burden on healthcare costs. The purpose of the present study was to investigate the protective effect of fluoxetine against MAinduced chronic pulmonary inflammation and to evaluate the potential role of nuclear factor erythroid 2-related factor 2 (Nrf2)-mediated antioxidative stress. Wistar rats were divided into control, MA and two fluoxetinetreated groups. Rats in the MA and the two fluoxetinetreated groups were treated daily with intraperitoneal injection of 10 mg/kg MA twice daily. Rats in the two fluoxetinetreated groups were injected intragastrically with fluoxetine (2 and 10 mg/kg) once daily, respectively. After 5 weeks, the rats were euthanized and hematoxylin and eosin staining, immunohistochemistry, western blot analysis and redox assay were performed. It was demonstrated that chronic exposure to MA can induce pulmonary inflammation in rats, with the symptoms of inflammatory cell infiltration, crowded lung parenchyma, thickened septum and a reduced number of alveolar sacs. Fluoxetine attenuated pulmonary inflammation and the expression of interleukin6 and tumor necrosis factorα in rat lungs. Fluoxetine inhibited MAinduced increases in the expression levels of serotonin transporter (SERT) and pp38 mitogenactivated protein kinase (MAPK), and reversed the MAinduced decrease in nuclear Nrf2 and human heme oxygenase1 in lungs. Fluoxetine at 10 mg/kg significantly reversed the reduced glutathione (GSH) level, the ratio of GSH/oxidized glutathione, and the reactive oxygen species level in rat lungs from the MA group. These findings suggested that fluoxetine, a SERT inhibitor, has a protective effect against MAinduced lung inflammation by suppressing oxidative stress through the SERT/p38 MAPK/Nrf2 pathway in rats.