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

Management of Accidental Paraquat Ingestion in a Child

AIM

To report on the management of a toddler who had accidental ingestion of an unknown amount of paraquat, with treatment including continuous renal replacement therapy (CRRT), steroids and antifibrinolytics at a tertiary-level health system.

METHODS

A 16-month-old child weighing 10 kg accidentally ingested an unknown amount of Gramoxone containing paraquat. The child was transferred to a tertiary centre Paediatric Intensive Care Unit (PICU) where she was electively intubated and commenced on CRRT at 7 hours and 15 minutes post-ingestion. She was also treated with activated charcoal, methylprednisolone, N-acetylcysteine infusion and pirfenidone. Paraquat blood and urine samples were monitored throughout her PICU admission.

RESULTS

The child did not exhibit respiratory distress or significant hypoxia during the admission. She developed ulceration of the lips, mouth and tongue on day 2 which improved after 48 hours. Feed intolerance and pneumatosis intestinalis were managed conservatively. Interstitial changes were noted on chest x-ray on day 3 and pirfenidone was initiated to minimise the risk of pulmonary fibrosis. The child was discharged from PICU to the general ward for further observation. At follow-up, there has been no evidence of pulmonary fibrosis up to 6 months post-discharge.

CONCLUSIONS

This case highlights the toxicity of Paraquat and importance of early management and urgent transfer of paraquat poisoning cases to specialised medical centres. Prompt interventions including activated charcoal, N-acetylcysteine, CRRT and pirfenidone can improve patient prognosis and reduce the risk of long-term complications such as pulmonary fibrosis in paediatric paraquat toxicity.

Immunomodulatory effect of glabridin in ovalbumin induced allergic asthma and its comparison with methylprednisolone in a preclinical rodent model

Glabridin, a polyphenolic flavonoid derived from Glycyrrhiza glabra (licorice) roots, has shown anti-inflammatory and antioxidant properties. The current study sought to investigate glabridin's immunomodulatory effect in ovalbumin induced allergic asthma. Healthy male Wistar rats were divided into five groups. Group I served as a control group. Asthma was induced in groups II- IV. Groups III and IV were treated with glabridin (40 mg/kg) and methylprednisolone (15 mg/kg), respectively. Inflammatory cells counts were determined in blood and bronchoalveolar lavage fluid (BALF). Serum IgE levels and levels of catalase, superoxide dismutase and glutathione peroxidase in lung homogenate were measured. The levels of mRNA expression of pro-inflammatory, anti-inflammatory and oxidative stress markers were analysed. Delayed type hypersensitivity (DTH) and acute toxicity of glabridin were also checked. Glabridin significantly decreased inflammatory cells in the blood and BALF. It increased the concentration of antioxidant enzymes catalase, superoxide dismutase and glutathione peroxidase. Glabridin markedly decreased serum IgE levels and DTH when compared to asthmatic rats. It significantly alleviated the expression of TNF-α, IL-4, IL-5, CXCL1, iNOS, and NF-κB. Administering 10 times the therapeutic dose of glabridin did not show any signs of acute toxicity. Findings suggest that glabridin has the potential to ameliorate allergic asthma and its effects are comparable to those of methylprednisolone. The immunomodulatory effect of glabridin might be contributed by the suppression of pro-inflammatory cytokines, oxidative stress markers, IgE antibodies, and elevation of antioxidant enzymes, suggesting future study and clinical trials to propose it as a candidate to treat allergic asthma.

Evaluation of the effectiveness of oxytocin and enalapril in the prevention of epidural fibrosis developed after laminectomy in rats

INTRODUCTION

Except for methylprednisolone, there is no current low-cost and low-side-effect drug/barrier method to prevent epidural fibrosis after spine surgery. However, the use of methylprednisolone has led to substantial controversy because of its serious side effects on wound healing. This study aimed to evaluate the effects of enalapril and oxytocin on preventing the development of epidural fibrosis in a rat laminectomy model.

MATERIALS

Under sedation anesthesia, T9, T10, and T11 laminectomy was performed on 24 Wistar Albino male rats. The animals were then separated into four groups; Sham group (only laminectomy was performed; n = 6), MP group (laminectomy was performed and 10 mg/kg/day methylprednisolone was administered intraperitoneally (ip) for 14 days; n = 6), ELP group (laminectomy was performed and 0.75 mg/kg/day enalapril was administered ip for 14 days; n = 6), OXT group (laminectomy was performed and 160 µg/kg/day oxytocin was administered ip for 14 days; n = 6). Four weeks after the laminectomy, all the rats were euthanised, and the spines were removed for histopathological, immunohistochemical, and biochemical examinations.

RESULTS

Histopathological examinations revealed that the degree of epidural fibrosis (X²=14.316, p = 0.003), collagen density (X²=16.050, p = 0.001), and fibroblast density (X²=17.500, p = 0.001) was higher in the Sham group and lower in the MP, ELP, and OXT groups. Immunohistochemical examinations showed that collagen type 1 immunoreactivity was higher in the Sham group and lower in the MP, ELP, and OXT groups (F = 54.950, p < 0.001). The highest level of α-smooth muscle actin immunoreactivity was seen in the Sham and OXT groups, and the lowest was in the MP and ELP groups (F = 33.357, p < 0.001). Biochemical analysis revealed that tissue levels of TNF-α, TGF-β, IL-6, CTGF, caspase-3, p-AMPK, pmTOR, and mTOR/pmTOR were higher in the Sham group and lower in MP, ELP, and OXT groups (p < 0.05). The GSH/GSSG levels were lower in the Sham group and higher in the other three groups (X²=21.600, p < 0.001).

CONCLUSION

The study results showed that enalapril and oxytocin, which are known to have anti-inflammatory, antioxidant, anti-apoptotic, and autophagy-related regenerative properties, could reduce the development of epidural fibrosis after laminectomy in rats.

Study on the Efficacy and Safety of Ambroxol Combined with Methylprednisolone in Patients with Acute Lung Injury

Background

There is no better treatment method towards paraquat-induced acute lung injury (ALI) at present. Ambroxol combined with methylprednisolone exhibits a significant improvement effect on ALI treatment, whereas their mechanism in ALI is still unclear.

Methods

64 patients with ALI caused by paraquat poisoning brought to our hospital from January 2015 to January 2018 were selected. They were separated into a combined treatment group (CTG) and a routine treatment group (RTG) on the basis of different treatment methods. The survival of patients was observed after 7 days of treatment. Arterial blood gas, oxygen partial pressure (PaO₂), partial pressure of carbon dioxide (PaCO₂), oxygenation index (PaO₂/FiO₂), patient's spontaneous respiratory rate (RR), tidal volume (VT), and positive end-expiratory pressure (PEEP) were observed before and after treatment for 7 days. Interleukin 6 (IL-6) and tumor necrosis factor α (TNF-α) were analyzed. The differences of indexes between the dead patients and the survivors were observed, and the potential predictive value of death was analyzed.

Results

After treatment, the indexes of patients were significantly improved in both groups compared with those before therapy. Further comparison showed that the improvement of PaO₂, PaCO₂, and PaO₂/FiO₂ in CTG was obviously higher than that in RTG (p < 0.05). The improvement of RR, PEEP, and VT in CTG was obviously higher than that in RTG (p < 0.05). The decreased degree of IL-6 and TNF-α in CTG was higher than that in RTG (p < 0.05). The 7-day mortality rate of 64 patients was 39.06%, and there was no obvious difference in the 7-day survival rate in both groups (p = 0.649). IL-6 and TNF-α were expected to be potential prediction indexes of paraquat-induced ALI.

Conclusion

Ambroxol combined with methylprednisolone significantly improved the oxygen partial pressure and oxygenation index of patients with paraquat-induced ALI and inhibited the inflammatory response of patients.

The herbicide paraquat-induced molecular mechanisms in the development of acute lung injury and lung fibrosis

The herbicide paraquat (PQ; 1,1'-dimethyl-4,4'-bipyridylium dichloride) is a highly toxic organic heterocyclic herbicide that has been widely used in agricultural settings. Since its commercial introduction in the early 1960s, numerous cases of fatal PQ poisonings attributed to accidental and/or intentional ingestion of PQ concentrated formulations have been reported. The clinical manifestations of the respiratory system during the acute phase of PQ poisoning mainly include acute lung injury (ALI)/acute respiratory distress syndrome (ARDS), followed by pulmonary fibrosis in a later phase. The focus of this review is to summarize the most recent publications related to PQ-induced lung toxicity as well as the underlying molecular mechanisms for PQ-mediated pathologic processes. Growing sets of data from in vitro and in vivo models have demonstrated the involvement of the PQ in regulating lung oxidative stress, inflammatory response, epigenetics, apoptosis, autophagy, and the progression of lung fibrosis. The article also summarizes novel therapeutic avenues based on a literature review, which can be explored as potential means to combat PQ-induced lung toxicity. Finally, we also presented clinical studies on the association of PQ exposure with the incidence of lung injury and pulmonary fibrosis.

Combined signaling of NF-kappaB and IL-17 contributes to Mesenchymal stem cells-mediated protection for Paraquat-induced acute lung injury

BACKGROUND

Paraquat (PQ) is an herbicide widely used in the world. PQ can cause pulmonary toxicity and even acute lung injury. Treatment for PQ poisoning in a timely manner is still a challenge for clinicians. Mesenchymal stem cell (MSC) transplantation has hold potentials for the treatment of several lung diseases including PQ poisoning. The aim of this study is to examine the mechanisms mediated by MSC transplantation to protect PQ-induced lung injury.

METHODS

Here we performed the whole genome sequencing and compared the genes and pathways in the lung that were altered by PQ or PQ together with MSC treatment.

RESULTS

The comparison in transcriptome identified a combined mitigation in NF-kappaB signaling and IL-17 signaling in MSC transplanted samples.

CONCLUSION

This study not only reiterates the important role of NF-kappaB signaling and IL-17 signaling in the pathogenesis of PQ-induced toxicity, but also provides insight into a molecular basis of MSC administration for the treatment of PQ-induced toxicity.

Bacopa monnieri alleviates paraquat induced toxicity in Drosophila by inhibiting jnk mediated apoptosis through improved mitochondrial function and redox stabilization

Paraquat (PQ) is an organic chemical compound and a member of redox active family of heterocycles. In spite of its high toxicities, it is used as one of the potent herbicide throughout the world. Though its toxic manifestations are observed in different organs, its principal toxic effect is manifested in the brain leading to the development of Parkinsonian symptoms. PQ exposure adversely affects dopaminergic (DA-ergic) neuron-rich region in the substantia nigra pars compacta (SNPC) of brain in the animal models of Parkinson's disease (PD), thereby mimicking PD like symptoms. Currently, lack of a potential drug to counter the toxic effect of PQ makes the management difficult. Bacopa monnieri extract (BME) has been shown to have promising effect against neurodegenerative disorders. Therefore, the present study evaluated the role of BME against PQ induced toxicity in Drosophila model of PD, the results of which are reproducible in higher animal models including human subjects. Here, we showed that BME treatment attenuates acute PQ induced toxicity in Drosophila by decreasing mortality and improving climbing ability. BME functions by optimizing redox equilibrium, mitochondrial function and depreciating apoptosis level. The underlying mechanisms were attributed to optimization of active JNK and cleaved Caspase-3 activity along with transcriptional stabilization of the genes regulating oxidative stress and apoptosis (jnk, caspase-3, damb and nrf-2). These results showed therapeutic efficacy of BME against PQ toxicity in the brain. Our results pave the way for further detailed analysis of BME to combat the development of Parkinson's like symptoms following exposure to PQ toxicity in the brain of higher animal models.

Patients with mild paraquat poisoning treated with prolonged low-dose methylprednisolone have better lung function: A retrospective analysis

Lung dysfunction is an important characteristic of injury induced by paraquat (PQ). This study aimed to evaluate the effects of prolonged low-dose methylprednisolone (MP) treatment on lung function in patients with mild PQ poisoning. We analyzed the results of lung function testing in all patients with mild PQ poisoning admitted to Cangzhou Central Hospital between January 2012 and August 2017. Patients were grouped according to short-term treatment (3 mg/kg/day MP for 3 days) or prolonged treatment (3 mg/kg/day MP for 3 days, followed by dosage reduction by half every 3 days, with treatment terminated when a dosage of 0.375 mg/kg/day was reached). Lung function was evaluated at 2 to 3 months after PQ exposure. The forced expiratory volume in 1 second (85.72 ± 4.93% vs 78.41 ± 4.58%; P < .001), forced vital capacity (81.98 ± 4.93% vs 77.85 ± 4.37%; P < .001), and diffusing capacity (84.27 ± 5.16% vs 76.21 ± 3.71%; P < .001) in the prolonged low-dose MP group were improved compared with those in the short-term MP group. Patients with mild PQ poisoning treated with prolonged low-dose MP had better lung function 2 to 3 months after PQ poisoning.