Suspended particulate matter promotes epithelial-to-mesenchymal transition in alveolar epithelial cells via TGF-β1-mediated ROS/IL-8/SMAD3 axis

Epidemiological evidence presents that dust storms are related to respiratory diseases, such as pulmonary fibrosis (PF). However, the precise underlying mechanisms of SPM-elicited adverse effects still need to be investigated. Epithelial-mesenchymal transition (EMT) process is a characteristic of PF. We discussed whether suspended particulate matter (SPM) is involved in EMT induction via transforming growth factor-β1 (TGF-β1). In this study, a detailed elemental analysis (55 elements), particle size, and morphology were determined. To investigate the toxicity of SPM, an MTT test was performed to detect cell viability. Next, A549 cells were exposed to selected concentrations of SPM (20 and 40 µg/mL) for single and repeated exposures. The DCFH-DA assay showed that exposure to SPM could produce reactive oxygen species (ROS). The ELISA assay demonstrated increased levels of interleukin-8 (IL-8) and TGF-β1 in the supernatant. Western blot was used to detect the expression of proteins associated with EMT and the SMAD3-dependent pathway. Results of western blot demonstrated that E-cadherin was reduced, whereas p-SMAD3, vimentin, and α-smooth muscle actin were elevated. Our findings indicated that SPM triggered EMT by induction of oxidative stress, inflammation, and the TGF-β1/SMAD3 pathway activation.

The impact of COVID-19 pandemic lockdowns on air quality index: a systematic review

During the outbreak of the novel coronavirus disease 2019 (COVID-19), many countries implemented lockdown policies to control its transmission. These restrictions provided an opportunity to rest and recover the environment. This systematic review (SR) aimed to evaluate the impact of COVID-19 lockdowns on the Air Quality Index (AQI) in countries worldwide. ScienceDirect and PubMed were searched using relevant keywords to identify studies published until March 2020. Overall, 20 studies were included in the SR based on the eligibility criteria. The results show that COVID-19-related lockdown policies positively affect AQI by restricting air-polluting activities, such as transportation, industry, and construction. However, it is important to note that these policies are ineffective in controlling sources of natural air pollution and local dust. The findings of this study emphasize the need for policymakers to approve legislation limiting the sources of air pollutants.

Zingerone Alleviates Morphine Tolerance and Dependence in Mice by Reducing Oxidative Stress-Mediated NLRP3 Inflammasome Activation

Morphine (MPH) is widely used for pain management; however, long-term MPH therapy results in antinociceptive tolerance and physical dependence, limiting its clinical use. Zingerone (ZIN) is a natural phenolic compound with neuroprotective effects. We investigated the effects of single and repeated doses of ZIN on MPH-induced tolerance, dependence, and underlying biochemical mechanisms. After a dose-response experiment, tolerance was developed to MPH (10 mg/kg, i.p.) for seven days. In the single-dose study, ZIN was administered on day seven. In the repeated-dose study, ZIN was administered for seven days. Naloxone (5 mg/kg, i.p., 120 min after MPH) was injected to assess withdrawal signs on day seven. The levels of thiobarbituric acid reactive substances (TBARS), nitric oxide (NO), total thiol (TT), and glutathione peroxidase (GPx) were measured in the prefrontal cortex. The protein levels of interleukin-1 beta (IL-1β) and NLRP3-ASC-Caspase-1 axis were assessed by ELISA and Western blotting, respectively. Results showed that ZIN (100 mg/kg) had no antinociceptive activity, and subsequent experiments were performed at this dose. Repeated ZIN reversed MPH antinociceptive tolerance, whereas single ZIN did not. Single and repeated ZIN attenuated naloxone-induced jumping. In addition, repeated ZIN significantly inhibited weight loss. Repeated ZIN suppressed the MPH-induced increase in TBARS, NO, IL-1β, NLRP3, ASC, and Caspase-1. It also inhibited MPH-induced TT and GPx reduction. In contrast, single ZIN had no effect. Findings suggest that ZIN reduces MPH-induced tolerance and dependence by suppressing oxidative stress and NLRP3 inflammasome activation. This study provides a novel therapeutic approach to reduce the side effects of MPH.

Metformin alleviates sodium arsenite-induced hepatotoxicity and glucose intolerance in mice by suppressing oxidative stress, inflammation, and apoptosis

BACKGROUND

Epidemiological studies have shown that exposure to sodium arsenite (NaAsO2) causes diabetes and hepatotoxicity. Metformin (MET), an oral hypoglycemic agent, has long been used in diabetes therapy. In addition, MET has been shown to have hepatoprotective effects. In this study, we investigated the effects of MET on NaAsO2-induced hepatotoxicity and glucose intolerance in mice.

METHODS

Mice were divided into four groups: Groups I and II received distilled water and NaAsO2 (10 mg/kg, p.o.) for five weeks, respectively. Groups III and IV were treated with NaAsO2 (10 mg/kg, p.o.) for three weeks, followed by MET (125 and 250 mg/kg, p.o.) for the last two weeks before NaAsO2. A glucose tolerance test was performed on day 35. The serum and tissue parameters were also evaluated.

RESULTS

Histopathological examination revealed NaAsO2-induced liver and pancreatic damage. NaAsO2 caused hyperglycemia, glucose intolerance, and a significant increase in liver function enzymes. Administration of NaAsO2 significantly reduced hepatic superoxide dismutase, catalase, glutathione peroxidase, and total thiol levels and increased the content of reactive thiobarbituric acid substances. In addition, it led to an increase in liver nitric oxide levels and protein expression of tumor necrosis factor-α, nuclear factor kappa B, and cysteine-aspartic proteases-3. In contrast, treatment with MET (250 mg/kg) significantly improved NaAsO2-induced biochemical and histopathological changes.

CONCLUSION

Our findings suggest that the significant effects of MET against NaAsO2-induced hepatotoxicity and glucose intolerance may be exerted via the regulation of oxidative stress, followed by suppression of inflammation and apoptosis.

PMSF Attenuates Morphine Antinociceptive Tolerance and Dependence in Mice: Its Association with the Oxidative Stress Suppression

Opioids use has been limited due to tolerance and dependence as major unwanted effects. Previous evidence has shown that targeting endocannabinoid signaling can prevent the development of opioid tolerance and dependence. This study was designed to evaluate the effect of phenylmethylsulfonyl fluoride (PMSF), an inhibitor of fatty acid amide hydrolase (FAAH), on morphine antinociceptive tolerance and physical dependence in mice. The antinociceptive effects of PMSF at the doses 60, 120, and 300 mg/kg were investigated. Results showed that PMSF has a notable antinociceptive effect at doses 120 and 300 mg/kg. The dose of (60 mg/kg, i.p.) PMSF was considered as a sub-antinociceptive dose. Morphine tolerance and dependence were induced by twice-daily injection of morphine (10 mg/kg, s.c.) for 10 consecutive days and the last dose on day 11. Tolerance was assessed by the hot-plate test and dependence by naloxone-precipitated morphine withdrawal signs. In the brain, oxidative stress markers include activities of glutathione peroxidase, catalase, superoxide dismutase, and levels of malondialdehyde and glutathione were determined. A sub-antinociceptive dose (60 mg/kg) of PMSF could reduce tolerance in both acute and chronic methods of administration. However, alleviation of dependence and suppression of oxidative stress markers occurred in the chronic administration of PMSF. In conclusion, it seems that PMSF can suppress morphine tolerance and dependence. However, more studies are needed to clarify its mechanism.