Methylprednisolone effects on oxygenation and histology in a rat model of acute lung injury

Potential therapeutic and ameliorative effects of ramipril alone and in combination with methylprednisolone for the cytokine releasing syndrome in mice: An in vivo study

Cytokine-releasing syndrome (CRS) is a special form of systemic inflammatory response syndrome provoked by factors like viral infections and certain immunomodulatory drugs like monoclonal antibodies and adoptive T therapy. To elucidate the potential role of ramipril (RM) and its combination with methylprednisolone (MP) against the development and progression of CRS in mice. This experiment consists of two parts: protective and therapeutic interventions. The protective experiment: in the induction group, mice received an intraperitoneal injection (IP) of 5mg/kg lipopolysaccharide (LPS) without intervention. The other groups received various drugs before the induction by three days, then observed for an additional two days (50 mg/kg MP, 3 mg/kg RM, and a combination of 1.5 mg/kg RM with 25 mg/kg MP). The second part of the study involves the therapeutic potential; all groups received similar doses of drugs in the prevention groups, except LPS induction was given first, and after one hour, the mice received daily doses of the drugs for five days. At the end of the experiment, blood and tissue samples were obtained. Mice treated with RM and its combination with MP showed improved serum TNF-α, IL-6, IL-8, IL-1β, INF-γ, MDA, and GSH in both prevention and therapeutic groups. Histopathologically, mice treated with ramipril and its combination with MP ameliorate the tissue damage in both lung and liver tissues following LPS induction. Ramipril showed protective and therapeutic effects in LPS-induced cytokine storms in mice through anti-inflammatory and antioxidant mechanisms.

Novel therapeutic effects of rifaximin in combination with methylprednisolone for LPS-induced ‎oxidative stress and inflammation in mice‎: ‎An in vivo study

Cytokine-releasing syndrome (CRS) is a special form of ‎‎systemic inflammatory response syndrome provoked by ‎factors ‎like viral infections and certain immunomodulatory drugs.‎ To elucidate the potential ‎role of rifaximin (RIF) and its combination with methylprednisolone (MP) against the development and ‎progression of CRS in ‎mice.‎ This experiment consists of two parts: protective and therapeutic interventions. The protective experiment: in the induction group, mice received an intraperitoneal injection (IP) of 5 mg/kg lipopolysaccharide (LPS) without intervention. The other group received various drugs before the induction by three days, then observed for an additional two days (50 mg/kg MP, 50 mg/kg RIF, and a combination of 25 mg/kg RIF with 25 mg/kg MP. The second part of the study involves the therapeutic potential; all groups received similar doses of drugs to that received in the prevention groups, except LPS induction was given first, and after one hour, the mice received daily doses of the drugs for five days. At the end of the experiment, blood and tissue samples were obtained. Mice treated with RIF and its combination with MP showed improved serum TNF-α, IL-6, IL-8, IL-1β, INF-γ, MDA, and GSH in both prevention and therapeutic groups. Histopathologically, mice treated with rifaximin and its combination with MP ameliorates the tissue damage in both lung and liver tissues following LPS induction. In conclusion, rifaximin showed protective and therapeutic effects in LPS-induced cytokine storms in mice through anti-inflammatory and antioxidant mechanisms, and its combination with methylprednisolone showed additive/ synergistic action.

Methylprednisolone alleviates lung injury in sepsis by regulating miR-151-5p/USP38 pathway

BACKGROUND

Acute lung injury (ALI) is manifested by increased blood vessel permeability within the lungs and subsequent impairment of alveolar gas exchange. Methylprednisolone (MP) is commonly used as a treatment for ALI to reduce inflammation, yet its molecular mechanism remains unclear. This study aims to explore the underlying mechanisms of MP on ALI in a model induced by lipopolysaccharide (LPS).

MATERIAL AND METHODS

The proliferation, viability, apoptosis, and miR-151-5p expression of alveolar type II epithelial cells (AECII) were detected using the cell EdU assay, Annexin V/PI Apoptosis Kit, counting kit-8 (CCK-8) assay, and RT-qPCR. Western blot analysis was used to detect the Usp38 protein level. IL-6 and TNF-α were measured by ELISA. The combination of miR-151-5p and USP38 was determined by chromatin immunoprecipitation (ChIP)-PCR and dual-luciferase reporter assay.

RESULTS

MP greatly improved pulmonary function in vivo, reduced inflammation, and promoted the proliferation of the alveolar type II epithelial cells (AECII) in vitro. By comparing the alterations of microRNAs in lung tissues between MP treatment and control groups, we found that miR-151-5p exhibited a significant increase after LPS-treated AECII, but decreased after MP treatment. Confirmed by a luciferase reporter assay, USP38, identified as a downstream target of miR-151-5p, was found to increase after MP administration. Inhibition of miR-151-5p or overexpression of USP38 in AECII significantly improved the anti-inflammatory, anti-apoptotic, and proliferation-promotive effects of MP.

CONCLUSION

In summary, our data demonstrated that MP alleviates the inflammation and apoptosis of AECII induced by LPS, and promotes the proliferation of AECII partially via miR-151-5p suppression and subsequent USP38 activation.

Electroacupuncture Pretreatment Exhibits Lung Protective and Anti-Inflammation Effects in Lipopolysaccharide-Induced Acute Lung Injury via SIRT1-Dependent Pathways

To investigate the effect of electroacupuncture (EA) on acute lung injury (ALI), a lipopolysaccharide (LPS) induced ALI mouse model was used in this study. Before receiving intratracheal LPS instillation, mice were given EA at ST36 for 7 days as a long-term treatment or one time as a short-term treatment. Lung histopathological examination, lung injury scores, lung wet/dry (W/D) ratio, and inflammatory cytokines included proinflammation factors such as TNF-α, IL-1β, and IL-6 and anti-inflammation factors such as IL-4 and IL-10 in serum and bronchoalveolar lavage fluid (BALF) were detected at the end of experiment. The results show that EA pretreatment ameliorated the lung damage and inflammatory response by LPS. In addition, we found that SIRT1 and its deacetylation of NF-κB were promoted after EA pretreatment in lung tissues. Meanwhile, the expression of angiotensin-converting enzyme 2 (ACE2) is also enhanced by EA pretreatment. Thus, the present findings suggest that EA could be a potential therapy of ALI.

Electroacupuncture pre‑conditioning protects from lung injury induced by limb ischemia/reperfusion through TLR4 and NF‑κB in rats

Limb ischemia/reperfusion (I/R) can induce inflammation, causing acute lung injury. The Toll-like receptor 4 (TLR4)/NF-κB pathway plays an important role in acute and chronic inflammatory disorders. Several studies have demonstrated the efficacy of acupuncture in lung inflammatory injury. The aim of the present study was to elucidate the mechanism underlying the protective effect of electroacupuncture (EA) against lung injury induced by limb I/R. EA applied at the Zusanli and Sanyinjiao acupoints attenuated lung injury and decreased the secretion of inflammatory factors such as tumor necrosis factor-α, interleukin (IL)-1, IL-6 and myeloperoxidase. Moreover, the expression levels of TLR4 and NF-κB were suppressed by EA. Thus, the present findings suggested that EA can reduce pulmonary inflammation induced by limb I/R injury, possibly via the inhibition of the TLR4/NF-κB pathway.

The Protection Potential of Antioxidant Vitamins Against Acute Respiratory Distress Syndrome: a Rat Trial

Acute respiratory distress syndrome (ARDS) is a fatal disease that includes inflammation formed by septic and non-septic causes. Reactive oxygen radicals (ROS) play a key role in ARDS pathophysiology and constitute the base of damage process. Antioxidant vitamins are used for inhibiting hazardous effects of radicals. Therefore, effects of antioxidant vitamins such as α-lipoic acid (ALA), vitamin E (VITE), and C (VITC) were investigated on oleic acid (OA)-induced ARDS rat model. Furthermore, high and low dose of methylprednisolone (HDMP, LDMP) was used for comparing effects of the vitamins. In this study, 42 male rats were divided to seven groups named control, OA, ALA, VITE, VITC, LDMP, and HDMP. OA was intravenously administered to all groups except control group and other compounds were orally administered (ALA, VITE, and VITC: 100 mg/kg, LDMP: 5 mg/kg, HDMP: 50 mg/kg) after OA injections. OA increased MDA level in lung tissue and TNF-α and IL-1β cytokine levels in serum. ALA, VITE, VITC, and both dose of MP significantly decreased the cytokine levels. Although OA reduced SOD, CAT, and GSH levels in lung tissue, the vitamins and LDMP markedly enhanced the levels except for HDMP. Furthermore, OA showed thickening in bronchi and alveolar septum, hyperemia in vessels, and inflammatory cell infiltrations in lung tissue histopathological examinations. Antioxidant vitamins may be useful for premedication of ARDS and similar disorders. However, methylprednisolone was not found sufficient for being a therapeutic agent for ARDS.

Corticosteroids in Acute Lung Injury: The Dilemma Continues

Acute lung injury (ALI) represents a serious heterogenous pulmonary disorder with high mortality. Despite improved understanding of the pathophysiology, the efficacy of standard therapies such as lung-protective mechanical ventilation, prone positioning and administration of neuromuscular blocking agents is limited. Recent studies have shown some benefits of corticosteroids (CS). Prolonged use of CS can shorten duration of mechanical ventilation, duration of hospitalization or improve oxygenation, probably because of a wide spectrum of potentially desired actions including anti-inflammatory, antioxidant, pulmonary vasodilator and anti-oedematous effects. However, the results from experimental vs. clinical studies as well as among the clinical trials are often controversial, probably due to differences in the designs of the trials. Thus, before the use of CS in ARDS can be definitively confirmed or refused, the additional studies should be carried on to determine the most appropriate dosing, timing and choice of CS and to analyse the potential risks of CS administration in various groups of patients with ARDS.

Neutrophil-lymphocyte ratio as an early predictor for patients with acute paraquat poisoning: A retrospective analysis

This retrospective study aimed to investigate whether the neutrophil-lymphocyte ratio (NLR) can be used as an early predictor of 90-day survival in patients with acute paraquat (PQ) poisoning.This study enrolled 105 patients with acute PQ poisoning admitted from May 2012 to May 2018. Kaplan-Meier curve, receiver operating characteristic curve, and Cox proportional hazards regression analyses were used to investigate the predictive value of NLR for 90-day survival of patients with acute PQ poisoning.The 90-day survival rate was 40.95% (43/105). Survivors had lower NLR (P <.001), which was an independent predictor of 90-day survival according to the Cox proportional hazard regression analyses. The area under the NLR curve was 0.842 (95% CI: 0.767-0.917, P <.001) in predicting 90-day survival.Our findings showed that low NLR was a valuable early predictor of 90-day survival in patients with acute PQ poisoning.

Prolonged methylprednisolone therapy after the pulse treatment for patients with moderate-to-severe paraquat poisoning: A retrospective analysis

This retrospective study aims to evaluate the effect of prolonged methylprednisolone (MP) therapy on the mortality of patients with moderate-to-severe paraquat (PQ) poisoning after the pulse treatment.We performed a retrospective analysis of patients with acute moderate-to-severe PQ poisoning that were admitted to the emergency department from May 2012 to August 2016. Out of 138 patients, 60 were treated with pulse treatment (15 mg kg day MP for 3 days) and 78 were treated with prolonged MP therapy after pulse treatment (15 mg kg day MP for 3 days; afterward, the dosage was reduced in half every 2 days, and the MP therapy was terminated until 0.47 mg kg day). Kaplan-Meier method was used to compare the mortality between the 2 groups. Cox proportional hazard models were used to estimate the hazard ratios (HR) and 95% confidence intervals (CI).The mortality of the prolonged MP therapy after pulse treatment group was lower than that of the pulse group (47.4% vs 63.3%; log-rank tests, P  =  .003). According to the multivariate Cox analysis, the prolonged MP therapy after pulse treatment was significantly associated with a lower mortality risk (HR: 0.31, 95% CI: 0.19-0.52, P < .001) compared with the pulse group. In addition, the prolonged MP therapy after pulse treatment caused more incidences of leucopenia than the pulse treatment alone (25.6% vs 11.7%, P  =  .04).The prolonged MP therapy after pulse treatment can reduce the mortality of moderate-to-severe PQ poisoning patients.

Effects of prolonged methylprednisolone treatment after pulse therapy for paraquat-intoxicated rats

OBJECTIVE

This study was designed to evaluate prolonged methylprednisolone (MP) treatment after pulse therapy for paraquat (PQ)-intoxicated rats.

METHOD

Acute PQ toxicity was induced by intraperitoneally injecting single toxic dose of 25 mg/kg of body weight. Rats were divided into four groups: control group (saline solution for 15 days), PQ group (saline solution for 15 days after PQ toxicity), pulse group (15 mg·kg^-1·day^-1 MP for 3 days after PQ toxicity and then saline solution for 12 days) and pulse + prolonged group (15 mg·kg^-1·day^-1 MP for 3 days after PQ toxicity; dosage was subsequently reduced by half every 2 days, and MP was terminated until 0.47 mg·kg^-1·day^-1). Hydroxyproline (HYP) content in lung tissues was evaluated through enzyme-linked immunosorbent assay, and lung fibrosis was examined using a semiquantitative scoring system (Ashcroft staging criteria). Lung wet-to-dry weight (W/Dc) ratio and 15-day survival rates of the rats were also analysed.

RESULTS

Similar survival rates (55.0 vs. 65.0%) were obtained for the pulse group and the pulse + prolonged group. The W/Dc (4.79 ± 0.42 vs. 5.29 ± 0.35), HYP content in the lung tissues (3.23 ± 0.24 vs. 3.72 ± 0.23 μg/mg) and lung fibrosis scores (2.69 ± 0.74 vs. 3.12 ± 0.60) of the pulse + prolonged group were lower than those of the pulse group.

CONCLUSION

Prolonged MP treatment after pulse therapy could effectively ameliorate PQ-intoxicated acute lung injury in rats. However, further studies should be performed to verify our findings.

Amelioration of Paraquat-Induced Pulmonary Injury by Mesenchymal Stem Cells

Acute paraquat (PQ) poisoning induces redox cycle and leads to fatal injury of lung. Clinical management is supportive in nature due to lack of effective antidote, and the mortality is very high. Mesenchymal stem cells (MSCs) process the properties of immunomodulation, anti-inflammatory, and antifibrotic effects and oxidative stress resistance. MSC transplantation may theoretically serve as an antidote in PQ intoxication. In this study, we examined the potential therapeutic effects of MSCs in PQ-induced lung injury. The degree of PQ toxicity in the rat type II pneumocyte cell line, L2, and MSCs was evaluated by examining cell viability, ultrastructural changes, and gene expression. L2 cells treated with 0.5 mM PQ were cocultured in the absence or presence of MSCs. For the in vivo study, adult male SD rats were administered an intraperitoneal injection of PQ (24 mg/kg body weight) and were divided into three groups: group I, control; group II, cyclophosphamide and methylprednisolone; group III, MSC transplantation 6 h after PQ exposure. MSCs were relatively resistant to PQ toxicity. Coculture with MSCs significantly inhibited PQ accumulation in L2 cells and upregulated the expression of antioxidative heme oxygenase 1 and metallothionein 1a genes, reversed epithelial-to-mesenchymal transition, and increased the viability of PQ-exposed L2 cells. Treatment with MSCs resulted in a significant reduction in severity of liver and renal function deterioration, alleviated lung injury, and prolonged the life span of rats. Altogether, our results suggest that MSCs possess antidote-like effect through multifactorial protection mechanism. The results of this preclinical study demonstrate that transplantation of MSCs may be a promising therapy and should be further validated clinically.

The harmful effect of prolonged high-dose methylprednisolone in acute lung injury

Although many literatures have shown that prolonged high-dose administration of corticosteroids is hazardous and not indicated to therapy acute lung injury (ALI), there is little information on the harmful effect of prolonged high-dose corticosteroids in acute lung injury. In this study, we aimed to investigate the effect of prolonged high-dose methylprednisolone (MPL) on ALI and improve knowledge regarding the appropriate use of corticosteroids in ALI. The different doses of MPL (3, 30, 180mg·kg(-1)) were given via tail vein injection 1h after the first time LPS administration and were daily administrated for 14days. Lung tissues and lavage samples were isolated for biochemical determinations and histological measurements at 12h, 7days and 14days after LPS administration. Single administration of 180mg·kg(-1) MPL decreased the lung injury score, wet-to-dry ratio, the total cell numbers and level of procollagen type III in BALF at 12h after LPS challenge. However, prolonged therapy with 180mg·kg (-1) MPL for 7days and 14days decreased the number of AMs in BALF and increased the above-mentioned indexes. These results suggested that the prolonged high-dose MPL has harmful effects to treat LPS-induced ALI in rats.

Acute pathophysiological effects of intratracheal instillation of budesonide and exogenous surfactant in a neonatal surfactant-depleted piglet model

BACKGROUND

Chronic lung disease continues to be a major complication in premature infants with severe respiratory distress syndrome (RDS). This is despite having advanced ventilatory care, prenatal corticosteroids, and postnatal surfactant therapies. The combined use of intratracheal corticosteroids and surfactant may not only recruit the lungs, but also alleviate pulmonary inflammation in severe RDS.

METHODS

Fifteen newborn piglets received repeated pulmonary saline lavage to induce surfactant-depleted lungs, mimicking neonatal RDS. They were randomly divided into three groups: control group receiving no treatment; surfactant (Surf) group, treated with standard intratracheally instilled surfactant (100 mg/kg); and Budesonide plus surfactant (Bude + Surf) group, treated with intratracheally administered mixed suspension of budesonide (0.5 mg/kg) and surfactant (100 mg/kg). Blood samples were taken every 30 minutes for 4 hours. Lung tissue was examined after the experiment.

RESULTS

Significantly better oxygenation with higher PaO(2) and alveolar-arterial oxygen difference was noted in the Surf and Bude + Surf groups, compared with the control group (p < 0.05), but there were no significant differences between the Surf and Bude + Surf groups. Pulmonary histologic damage was also markedly alleviated in both the Surf and Bude + Surf groups, compared with the control group, and lung injury scores were significantly decreased in the Surf and Bude + Surf groups, compared with the control group (p < 0.05).

CONCLUSIONS

Intratracheal instillation of surfactant or surfactant plus budesonide can improve oxygenation and pulmonary histologic outcome in neonatal surfactant-depleted lungs. The additional use of budesonide does not disturb the function of the exogenous surfactant. Intratracheal administration of a corticosteroid combined with surfactant may be an effective method for alleviating local pulmonary inflammation in severe RDS.

Establishing the use of melatonin as an adjuvant therapeutic against paraquat-induced lung toxicity in rats

It is well known that the intake of paraquat (PQ) causes severe tissue injury leading to numerous fatalities. Considering that the main target for PQ toxicity is the lung and involves the production of reactive oxygen and nitrogen species, transcription factors and inflammatory cytokines, it may be hypothesized that the combination of a potent antiinflammatory and antioxidant agent may counteract more of PQ's effects than an antiinflammatory agent alone. For this purpose, combination of dexamethasone (Dex) and melatonin (Mel) was compared with Dex alone. A total of 40 male Wistar albino rats were divided into four groups as control, PQ, Dex only, and Dex plus Mel. The animals were given intraperitoneally a toxic dose of 19 mg/kg PQ dissolved in 1 ml saline. Control animals were injected with the same amount of saline only. A dose of 1 mg/kg Dex was administered 2 hrs after PQ administration. In the combination treatment group, 20 mg/kg Mel was given with Dex. All drugs were given every 12 hrs for a total of six doses. Five animals in PQ group and three animals in Dex only group died by the end of the study. No deaths occurred in the Dex+Mel group. Dex exerted improvements in several oxidative and antioxidative parameters. However, combination treatment provided beneficial effects against PQ toxicity far greater than Dex alone. This difference was also apparent when tissues were histologically compared. In conclusion, Mel exhibited strong additive beneficial effects with Dex and can be considered as a safe treatment modality against PQ toxicity.

P-glycoprotein induction: an antidotal pathway for paraquat-induced lung toxicity

The widespread use of the nonselective contact herbicide paraquat (PQ) has been the cause of thousands of deaths from both accidental and voluntary ingestion. The main target organ for PQ toxicity is the lung. No antidote or effective treatment to decrease PQ accumulation in the lung or to disrupt its toxicity has yet been developed. The present study describes a procedure that leads to a remarkable decrease in PQ accumulation in the lung, together with an increase in its fecal excretion and a subsequent decrease in several biochemical and histopathological biomarkers of toxicity. The administration of dexamethasone (100 mg/kg ip) to Wistar rats, 2 h after PQ intoxication (25 mg/kg ip), decreased the lung PQ accumulation to about 40% of the group exposed to only PQ and led to an improvement in tissue healing in just 24 h as a result of the induction of de novo synthesis of P-glycoprotein (P-gp). The involvement of P-gp in these effects was confirmed by Western blot analysis and by the use of a competitive inhibitor of this transporter, verapamil (10 mg/kg ip), which, given 1 h before dexamethasone, blocked its protective effects, causing instead an increase in lung PQ concentration and an aggravation of toxicity. In conclusion, the induction of P-gp, leading to a decrease in lung levels of PQ and the consequent prevention of toxicity, seems to be a new and promising treatment for PQ poisonings that should be further clinically tested.

Single high dose dexamethasone treatment decreases the pathological score and increases the survival rate of paraquat-intoxicated rats

Dexamethasone (DEX), a synthetic corticosteroid, has been successfully used in clinical practice during paraquat (PQ) poisonings due to its anti-inflammatory activity, although, as recently observed, its effects related to de novo synthesis of P-glycoprotein (P-gp), may also strongly contribute for its healing effects. The main purpose of this study was to evaluate the effects of a single high dose DEX administration, which induces de novo synthesis of P-gp, in the histological and biochemical parameters in lung, liver, kidney and spleen of acute PQ-intoxicated rats. Four groups of rats were constituted: (i) control group, (ii) DEX group (100 mg/kg i.p.), (iii) PQ group (25mg/kg i.p.) and (iv) PQ+DEX group (DEX injected 2h after PQ). The obtained results showed that DEX ameliorated the biochemical and histological lung and liver alterations induced by PQ in Wistar rats at the end of 24 hours. This was evidenced by a significant reduction in lipid peroxidation (LPO) and carbonyl groups content, as well as by normalization of the myeloperoxidase (MPO) activities. Moreover, DEX prevented the increase of relative lung weight. On the other hand, these improvements were not observed in kidney and spleen of DEX treated rats. Conversely, an increase of LPO and carbonyl groups content and aggravation of histological damages were observed in the latter tissues. In addition, MPO activity increased in the spleen of PQ+DEX group and urinary N-acetyl-beta-D-glucosaminidase activity, a biomarker of renal tubular proximal damage, also augmented in this group. Nevertheless, it is legitimate to hypothesize that the apparent protection of high dosage DEX treatment awards to the lungs of the PQ-intoxicated animals outweighs the increased damage to their spleens and kidneys, because a higher survival rate was observed, indicating that DEX treatment may constitute an important and valuable therapeutic drug to be used against PQ-induced toxicity.

High blood pressure is one of the symptoms of paraquat-induced toxicity in rats

This study investigated whether paraquat (Pq)-induced lipidic peroxidation (LP) is accompanied by changes in blood pressure and heart rate (HR) in rats. Groups of adult male Wistar rats were studied 2 and 12 h after Pq (35 mg/kg, i.p.) administration. The LP was evaluated by monitoring thiobarbituric acid reactive substances (TBARS) in the kidneys, liver and lungs, and validated by including a group treated with an antioxidant, superoxide dismutase (CuZnSOD 50,000 IU/kg), in the study. The TBARS levels were significantly higher (p<0.05) in the kidneys of the rats studied 2 h after Pq than in their respective controls. Similarly, systolic and diastolic blood pressure (DBP) were higher (p<0.05), while HR was lower (p<0.05) than basal levels 2 and 12 h after Pq administration. In contrast, the group treated simultaneously with Pq and CuZnSOD exhibited lower levels of TBARS (p<0.05) in all studied organs compared to the control group, while the mean arterial pressure and HR did not differ from those seen in the control group. These findings indicate that acute Pq poisoning symptoms include high blood pressure.