ABSTRACT
This study was aimed to explore the effect of angiotensin converting enzyme 2 (ACE2) agonist diminazene aceturate (DIZE) on acute lung injury (ALI) induced by limb ischemia-reperfusion (LIR) in mice. Male 8-week-old wild-type and hACE2 transgenic ICR mice were randomly divided into 6 groups (6 in each group), including wild-type control (W), wild-type model (WL), wild-type model with DIZE administration (WLD), transgenic control (T), transgenic model (TL), and transgenic model with DIZE administration (TLD) groups. LIR model was established by 4 h reperfusion following 2 h ischemia of bilateral hindlimbs with rubber bands in mice. The WLD and TLD groups were pretreated with DIZE (15 mg/kg, i.p.) for 4 weeks before LIR. At the end of LIR, the mice were sacrificed and lung tissues were sampled. Indexes for evaluating lung injury include organ coefficient and wet/dry weight ratio (W/D), cell count and protein concentration of bronchoalveolar lavage fluid (BALF), as well as morphological change and pathological score were detected. Angiotensin II (Ang II) and Ang (1-7) levels in lung tissue were determined by using ELISA commercial kits. And the protein expressions of angiotensin II type 1 receptor (AT1) and Mas receptor protein in lung tissue were detected by Western blot. The results were as follows: (1) There was obvious lung injury in both the WL and TL groups. The lung injury in the TL group was lighter than that in the WL group. DIZE could attenuate the lung injury in both the two groups. (2) The WL group showed increased Ang II and decreased Ang (1-7) levels, whereas the TL group did not exhibit any changes of these two proteins. DIZE decreased the level of Ang II in both the WL and TL groups, and increased the level of Ang (1-7) in the WL group. (3) In the WL and TL groups, AT1 and Mas receptor protein expressions were up-regulated. DIZE reversed the change of AT1 protein expression, whereas further increased Mas receptor expression in both the two groups. These results suggest that DIZE may improve the renin-angiotensin system homeostasis by regulating ACE2-Ang (1-7)-Mas axis in local lung tissue and play a protective role in LIR-induced ALI in mice.
ABSTRACT
The effects of nicotinamide adenine dinucleotide phosphate (NADPH) oxidase inhibitor apocynin on the enhanced hypoxia induced factor-1α (HIF-1α) and endothelin-1 (ET-1) expression, elevated systolic blood pressure under chronic intermittent hypoxia (CIH) condition and its action mechanism were investigated. Thirty healthy 8-week old Sprague-Dawley (SD) male rats were randomly divided into three groups (n=10 each): sham group, CIH group, and apocynin-treated CIH group. Tail artery systolic blood pressure was measured by tail-cuff method. Real-time fluorescence quantitative polymerase chain reaction (PCR) was used to detect the mRNA expression of HIF-1α and ET-1 in the carotid body, and the HIF-1α protein expression was examined by using Western blotting. The levels of malondialdehyde (MDA) and superoxide dismutase (SOD) were determined by using colorimetric method. In addition, the plasma ET-1 and HIF-1α levels were measured by using enzyme-linked immunosorbent assay. It was found that CIH exposure was associated with increased MDA levels, and apocynin-treated CIH animals showed reduction in MDA levels. Apocynin treatment prevented CIH-induced hypertension as well as CIH-induced decrease in SOD. The increases of HIF-1α and ET-1 mRNA along with HIF-1α protein expression in the carotid body, and elevated circulating HIF-1α and ET-1 levels were observed in CIH-exposed animals. Treatment with apocynin significantly decreased the ET-1 mRNA, HIF-1α protein expression and circulating HIF-1α level in CIH-exposed animals, and there was no statistically significant difference in the HIF-1α mRNA expression between CIH group and apocynin-treated group. These results indicated that apocynin alleviated CIH-induced hypertension by inhibiting NADPH oxidase, further leading to the reduced vasoconstrictor ET-1 level and oxidative stress. HIF-1α/ET-1 system signal pathway may interact with CIH-induced NADPH oxidase-dependent oxidative stress. Inhibition of NADPH oxidase activity may hopefully serve as a useful strategy for prevention and treatment of obstructive sleep apnea hypopnea syndrome-induced hypertension.
ABSTRACT
The effects of nicotinamide adenine dinucleotide phosphate (NADPH) oxidase inhibitor apocynin on the enhanced hypoxia induced factor-1α (HIF-1α) and endothelin-1 (ET-1) expression, elevated systolic blood pressure under chronic intermittent hypoxia (CIH) condition and its action mechanism were investigated. Thirty healthy 8-week old Sprague-Dawley (SD) male rats were randomly divided into three groups (n=10 each): sham group, CIH group, and apocynin-treated CIH group. Tail artery systolic blood pressure was measured by tail-cuff method. Real-time fluorescence quantitative polymerase chain reaction (PCR) was used to detect the mRNA expression of HIF-1α and ET-1 in the carotid body, and the HIF-1α protein expression was examined by using Western blotting. The levels of malondialdehyde (MDA) and superoxide dismutase (SOD) were determined by using colorimetric method. In addition, the plasma ET-1 and HIF-1α levels were measured by using enzyme-linked immunosorbent assay. It was found that CIH exposure was associated with increased MDA levels, and apocynin-treated CIH animals showed reduction in MDA levels. Apocynin treatment prevented CIH-induced hypertension as well as CIH-induced decrease in SOD. The increases of HIF-1α and ET-1 mRNA along with HIF-1α protein expression in the carotid body, and elevated circulating HIF-1α and ET-1 levels were observed in CIH-exposed animals. Treatment with apocynin significantly decreased the ET-1 mRNA, HIF-1α protein expression and circulating HIF-1α level in CIH-exposed animals, and there was no statistically significant difference in the HIF-1α mRNA expression between CIH group and apocynin-treated group. These results indicated that apocynin alleviated CIH-induced hypertension by inhibiting NADPH oxidase, further leading to the reduced vasoconstrictor ET-1 level and oxidative stress. HIF-1α/ET-1 system signal pathway may interact with CIH-induced NADPH oxidase-dependent oxidative stress. Inhibition of NADPH oxidase activity may hopefully serve as a useful strategy for prevention and treatment of obstructive sleep apnea hypopnea syndrome-induced hypertension.
Subject(s)
Animals , Male , Rats , Acetophenones , Antioxidants , Carotid Body , Metabolism , Endothelin-1 , Metabolism , Hypoxia , Drug Therapy , Metabolism , Hypoxia-Inducible Factor 1, alpha Subunit , Metabolism , NADP , Rats, Sprague-Dawley , Reactive Oxygen Species , Metabolism , Treatment OutcomeABSTRACT
<p><b>BACKGROUND</b>Obstructive sleep apnea (OSA) can cause cognitive dysfunction and may be a reversible cause of cognitive loss in patients with Alzheimer's disease (AD). Chronic exposure to intermittent hypoxia (IH), such as encountered in OSA, is marked by neurodegenerative changes in rat brain. We investigated the change of thioredoxin (Trx), spatial learning and memory in rats exposed to chronic intermittent hypoxia (CIH).</p><p><b>METHODS</b>Forty healthy male Sprague-Dawley (SD) rats were randomly divided into four groups of ten each: a CIH+normal saline (CIH+NS group), a N-acetylcystein-treated CIH (CIH+NAC) group, a sham CIH group (sham CIH+NS), and a sham NAC-treated sham CIH (CIH+NAC) group. Spatial learning and memory in each group was assessed with the Morris water maze. Real-time PCR and Western blotting were used to examine mRNA and protein expression of Trx in the hippocampus tissue. The terminal deoxynucleotidyl transferase-mediated dUTP-nick end-labeling (TUNEL) method was used to detect the apoptotic cells of the hippocampus CA1 region.</p><p><b>RESULTS</b>CIH-rats showed impaired spatial learning and memory in the Morris water maze, including longer mean latencies for the target platform, reduced numbers of passes over the previous target platform and a smaller percentage of time spent in the target quadrant. Trx mRNA and protein levels were significantly decreased in the CIH-hippocampus, meanwhile, an elevated apoptotic index revealed apoptosis of hippocampal neurons of rats exposed to CIH. The rats, which acted better in the Morris water maze, showed higher levels of the Trx mRNA and protein in the hippocampus; apoptotic index of the neurons in the hippocampus of each group was negatively correlated with the Trx mRNA and protein levels.</p><p><b>CONCLUSION</b>The Trx deficit likely plays an important role in the impaired spatial learning and memory in the rats exposed to CIH and may work through the apoptosis of neurons in the hippocampus.</p>
Subject(s)
Animals , Male , Rats , Apoptosis , Hippocampus , Pathology , Hypoxia , Learning Disabilities , Maze Learning , Memory Disorders , Rats, Sprague-Dawley , Sleep Apnea, Obstructive , Thioredoxins , PhysiologyABSTRACT
<p><b>AIM</b>To explore the effects of shenmai (Chinese transitional medicine) injection on lipid peroxidation in the lung following with ischemia/reperfusion (I/R) injury of limb.</p><p><b>METHODS</b>The models of I/R injury of limb were constructed in rabbits. Superoxide dismutase (SOD) and malondialdehyde (MDA) in into and out-flowing pulmonary blood (IPB, OPB) and lung tissue were measured, as well as the effects of shenmai injection were observed.</p><p><b>RESULTS</b>Compared with sham group, the activity of SOD in IPB, OPB and lung tissue were decreased, and the content of MDA was increased after 4 h ischemia followed by 4 h reperfusion. SOD increased and MDA decreased significantly by icy shenmai injection 30 min before reperfusion. The correlation analysis indicated that MDA was negatively correlated with SOD .</p><p><b>CONCLUSION</b>Oxygen free radicals metabolic confusion of lung occurred in the course of I/R, shenmai injection can alleviate lipid peroxidation, get rid of free radicals and inhibit the damage of lung.</p>
Subject(s)
Animals , Rabbits , Drug Combinations , Drugs, Chinese Herbal , Pharmacology , Therapeutic Uses , Extremities , Ischemia , Metabolism , Lipid Peroxidation , Lung , Metabolism , Malondialdehyde , Metabolism , Reperfusion Injury , Drug Therapy , Metabolism , Superoxide Dismutase , MetabolismABSTRACT
On a model of reperfusion after ischemia in the hind limbs (LIR) of rats, we used aminoguanidine (AG) which inhibits nitric oxide synthase (NOS) and L-arginine (L-Arg), one of the substrates in the process of nitric oxide synthesis, to observe the changes in NO, NOS, malondialdehyde (MDA), myeloperoxidase (MPO) and wet/dry ratio (W/D) in both skeletal muscles and the lung as well as the changes in phosphatidyl choline (PC) of lung surfactant. The morphologic changes were observed with microscopy. It was observed that the values of NOS, MPO, MDA of the muscle and lung in LIR group increased significantly and the content of PC decreased obviously compared with those of the normal control. Pulmonary observation revealed that after LIR leucocyte assembling and infiltration took place, which was dominated by polymorphocytes with broadened pulmonary interstitial tissue. In LIR+L-Arg group the above changes were reversed, and in LIR+AG group the injuries became more serious. The results obtained suggest that the activity of NOS and the production of NO following ischemia/reperfusion of hind limbs increased significantly, and that the endogenous NO may play a protective role during the early stage of acute lung injury after LIR.