Protective efficiacy of taurine against pulmonary edema progression: experimental study

Metabolomic analysis for the protective effects of mangiferin on sepsis-induced lung injury in mice

This study aimed to investigate the efficacy of mangiferin, including its known antioxidant and anti-inflammatory effects on sepsis-induced lung injury induced by a classical cecal ligation and puncture (CLP) models in mouse using a metabolomics approach. A total of 24 mice were randomly divided into four groups: the sham group was given saline before sham operation. The CLP group received the CLP operation only. HMF and LMF groups were given mangiferin treatment of high dose and low dose of mangiferin, respectively, before the CLP operation. One week after treatment, the mice were sacrificed and their lungs were collected for metabolomics analysis. We developed ultra-performance liquid chromatography coupled with quadrupole-time-of-flight mass spectrometry to perform lung metabolic profiling analysis. With the methods of principal component analysis and partial least squares discriminant analysis, 58 potential metabolites associated with amino acid metabolism, purine metabolism, lipid metabolism and energy regulation were observed to be increased or reduced in HMF and LMF groups compared with the CLP group. Conclusively, our results suggest that mangiferin plays a protective role in the moderation of sepsis-induced lung injury through reducing oxidative stress, regulating lipid metabolism and energy biosynthesis.

Hyperoxia arrests pulmonary development in newborn rats via disruption of endothelial tight junctions and downregulation of Cx40

This study investigated changes in vascular endothelial cell tight junction structure and the expression of the gene encoding connexin 40 (Cx40) at the early pneumonedema stage of hyperoxia‑induced bronchopulmonary dysplasia (BPD) in a newborn rat model. A total of 96 newborn rats were randomly assigned to one of the following two groups, the hyperoxia group (n=48) and the control group (n=48). A hyperoxia-induced BPD model was established for the first group, while rats in the control group were maintained under normoxic conditions. Extravasation of Evans Blue (EB) was measured; the severity of lung injury was assessed; a transmission electron microscope (TEM) was used to examine the vascular endothelial cell tight junction structures, and immunohistochemical assay, western blotting and reverse transcription-polymerase chain reaction (RT-PCR) were used to evaluate the expression of Cx40 at the mRNA and protein level. Our findings showed that injuries due to BPD are progressively intensified during the time-course of exposure to hyperoxic conditions. Pulmonary vascular permeability in the hyperoxia group reached the highest level at day 5, and was significantly higher compared to the control group. TEM observations demonstrated tight junctions between endothelial cells were extremely tight. In the hyperoxia group, no marked changes in the tight junction structure were found at days 1 and 3; paracellular gaps were visible between endothelial cells at days 5 and 7. Immunohistochemical staining revealed that the Cx40 protein is mainly expressed in the vascular endothelial cells of lung tissue. Western blotting and RT-PCR assays showed a gradual decrease in Cx40 expression, depending on the exposure time to hyperoxic conditions. However, the Cx40 mRNA level reached a trough at 5 days. Overall, our study demonstrated that exposure to hyperoxia damages the tight junction structures between vascular endothelial cells and downregulates Cx40. We therefore conclude that hyperoxia may participate in the regulation of pulmonary vascular endothelial permeability.

Reactive species and pulmonary edema

Pulmonary edema occurs when fluid flux into the lung interstitium exceeds its removal, resulting in hypoxemia and even death. Noncardiogenic pulmonary edema (NPE) generally results when microvascular and alveolar permeability to plasma proteins increase, one possible etiology being oxidant injury. Reactive oxygen and nitrogen species (RONS) can modify or damage ion channels, such as epithelial sodium channels, which alters fluid balance. Experimental systems in which either RONS are increased or protective antioxidant mechanisms are decreased result in alterations of epithelial sodium channel activity and support the hypothesis that RONS are important in NPE. Both basic and clinical studies are needed to critically define the RONS-NPE connection and the capacity of antioxidant therapy (either alone or as a supplement to β-agonists) to improve patient outcome.

Is there any cardioprotective role of Taurine during cold ischemic period following global myocardial ischemia?

Background

The aim of the present study was to investigate the cardioprotective effect of Taurine on the donor hearts during cold ischemic period.

Methods

32 rats were divided into four groups (sham, taurine, ischemia, treatment group, 8 rats in each). All rats were fed with rat food for three weeks. Taurine and treatment groups were given a 200 mg/kg/day dose of Taurine by oral gavage besides rat feed. Cardiectomy was performed in all rats after three weeks. In ischemia and treatment groups, harvested hearts were kept in 0.9% sodium chloride at +4 degrees C for 5 hours. Tissue samples were taken from left ventricle in all groups. These samples were evaluated by histopathologic and biochemical examination.

Results

In the present study results of the biochemical and histopathological examination reveals the protective effects of Taurine. As a marker of lipid peroxidation, Malondialdehyde (MDA) levels in ischemia group were significantly higher than both Sham and Taurine groups. MDA values were recorded; 3.62 ± 0.197 in the sham group, 2.07 ± 0.751 in the Taurine group, 9.71 ± 1.439 in the ischemia group and 7.68 ± 1.365 in the treatment group. MDA levels decreased in treatment group. (p < 0.05) In accordance with MDA findings, while superoxide dismutase and glutathione peroxidase levels decreased in ischemia group, they increased in treatment group. (p < 0.05) There was no differences in Catalase (CAT) enzyme level between treatment and ischemia group (p = 1.000). CAT level results were recorded; 7.08 ± 0.609 in the sham group, 6.15 ± 0.119 in the Taurine group, 5.02 ± 0.62 in the ischemia group, and 5.36 ± 0.384 in the treatment group. Less intracellular edema and inflammatory cell reaction were observed in histologic examination in favor of treatment group. (p < 0.01)

Conclusion

Taurine decreased myocardial damage during cold ischemic period following global myocardial ischemia.

The role of oxidative stress and effect of alpha-lipoic acid in reexpansion pulmonary edema - an experimental study

INTRODUCTION

We investigated the role of oxidative stress in the pathogenesis of reexpansion pulmonary edema (RPE) and effect of alpha-lipoic acid (ALA) in the prevention of RPE.

MATERIAL AND METHODS

There were 4 groups consisting of 10 rats in each group; control group (CG), α-lipoic acid group (ALAG), reexpansion pulmonary edema group (RPEG), reexpansion pulmonary edema plus α-lipoic acid group (RPE + ALAG). In all the groups, all rats were sacrificed 2 hours after the reexpansion of lungs. To indicate oxidative stress malondialdehyde (MDA), and to indicate antioxidant status superoxide dismutase (SOD), catalase (CAT) and glutathione peroxides (GPx) were measured in the lungs of rats.

RESULTS

Mean MDA value was lower in CG (7.02 ±0.14) and in ALAG (6.95 ±0.11) than the other groups (p = 0.001). It was highest in RPEG (8.89 ±0.21) (p = 0.001). It was lower in RPE + ALA G (7.21 ±0.32) than RPEG (p = 0.001). Antioxidant levels: GPx (37.21 ±3.01), CAT (2.87 ±0.14) and SOD (100.12 ±12.39) were lowest in RPEG among all groups (p = 0.001). These values were GPx (45.21 ±3.54), CAT (3.24 ±0.21) and SOD (172.36 ±15.48) in RPE + ALA G and were greater than those of RPEG (p = 0.001). While normal pulmonary parenchyma was seen in 2 rats in RPE + ALAG, it was not seen in RPEG. Pulmonary edema was seen in 1 rat in RPE + ALAG; however, it was seen in 3 in RPEG.

CONCLUSIONS

Oxidative stress might have an important role in the pathogenesis of RPE. In addition, ALA treatment might contribute in preventing RPE.

Reexpansion pulmonary edema

A reexpanziós tüdőödéma (RPE) egy ritkán előforduló kórállapot, amely rendszerint a krónikusan kollabált tüdő reexpanziója után jelentkezik. A klinikai manifesztáció széles skálán mozog a tünetmentes betegtől a halálos kimenetelig, amely utóbbi akár az esetek 20%-ában is előfordulhat. A patofiziológiai háttér komplex és máig nem teljesen tisztázott. Az ismert kockázati tényezők szem előtt tartásával és azok lehetőség szerinti kiküszöbölésével akár el is kerülhető az RPE kialakulása. Ez az összefoglaló megpróbál áttekintést adni a jelenlegi ismereteinkről, az RPE hátteréről, a terápiás lehetőségekről. Orv. Hetil., 2010,41,1708–1711.

Proanthocyanidin to prevent formation of the reexpansion pulmonary edema

Background

We aimed to investigate the preventive effect of Proanthocyanidine (PC) in the prevention of RPE formation.

Methods

Subjects were divided into four groups each containing 10 rats. In the Control Group (CG): RPE wasn't performed. Then subjects were followed up for three days and they were sacrificed after the follow up period. Samplings were made from tissues for measurement of biochemical and histopathologic parameters. In the Second Group (PCG): The same protocol as CG was applied, except the administration of PC to the subjects. In the third RPE Group (RPEG): Again the same protocol as CG was applied, but as a difference, RPE was performed. In the Treatment Group (TG): The same protocol as RPEG was applied except the administration of PC to the subjects.

Results

In RPEG group, the most important histopathological finding was severe pulmonary edema with alveolar damage and acute inflammatory cells. These findings were less in the TG group. RPE caused increased MDA levels, and decreased GPx, SOD and CAT activity significantly in lung tissue.

Conclusion

PC decreased MDA levels. Oxidative stress plays an important role in pathophysiology of RPE and PC treatment was shown to be useful to prevent formation of RPE.