Cynaroside ameliorates methotrexate-induced enteritis in rats through inhibiting NLRP3 inflammasome activation.

Introduction: Cynaroside exhibits various biological properties, including anti-inflammatory, antiviral, antitumor, and cardioprotective effects. However, its involvement in methotrexate (MTX)-induced intestinal inflammation remains inadequately understood. Thus, we investigated the impact of cynaroside on MTX-induced intestinal inflammation and its potential mechanisms. Methods: To assess the protective potential of cynaroside against intestinal inflammation, Sprague-Dawley rats were subjected to a regimen of 7 mg/kg MTX for 3 days, followed by treatment with cynaroside at varying doses (10, 20, or 40 mg/kg). Histopathological evaluations were conducted alongside measurements of inflammatory mediators to elucidate the involvement of the NLRP3 inflammasome in alleviating intestinal inflammation. Results: Administration of 7 mg/kg MTX resulted in decreased daily food intake, increased weight loss, and elevated disease activity index in rats. Conversely, treatment with cynaroside at 20 or 40 mg/kg ameliorated the reductions in body weight and daily food intake and suppressed the MTX-induced elevation in the disease activity index. Notably, cynaroside administration at 20 or 40 mg/kg attenuated inflammatory cell infiltration, augmented goblet cell numbers and lowered serum levels of tumor necrosis factor-α, interleukin (IL)-1ß, and IL-18, as well as the CD68-positive cell rate in the intestines of MTX-induced rats. Furthermore, cynaroside downregulated the expression levels of NLRP3, cleaved caspase 1, and cleaved IL-1ß in MTX-induced rats. Discussion: Collectively, our findings indicated that cymaroside alleviates intestinal inflammatory injury by inhibiting the activation of NLRP3 inflammasome in MTX-induced rats.

Aucubin alleviates methotrexate-induced enteritis in rats by inducing autophagy.

One of the toxic side effects of methotrexate (MTX) is enteritis. Aucubin, an iridoid glycoside derived from traditional medicinal herbs, has been proven to have anti-inflammation, anti-apoptosis and anti-oxidation properties. This work explored the effect and mechanism of aucubin in treating MTX-induced enteritis in a rat model. Two doses of aucubin (5 and 10 mg/kg) were adopted for the assessment of its pharmacological activity. We observed that in rats with MTX-induced enteritis, the body weight and small intestinal weight decreased. The intestine barrier was injured, as reflected by pathological examinations and an increase in D-lactate and diamine oxidase concentration in serum. Intestinal inflammation was shown by the observation of macrophages in the intestine and the concentrations of inflammatory cytokines tumour necrosis factor-α (TNF-α) and interleukin-6 (IL-6) in serum. The NLR family pyrin domain containing 3 (NLRP3) inflammasome was shown to be activated by the enhancement of NLRP3, cleaved-caspase 1, IL-18 and IL-1ß. Moreover, autophagy was reflected by transmission electron microscopy as slightly induced, along with changes in autophagy-related markers microtubule-associated protein 1 light chain 3 (LC3) and Beclin1. Remarkably, aucubin treatment attenuated the MTX-induced disease activity index increase, intestinal damage, inflammatory response and NLRP3 inflammasome activation, but provoked autophagy. Rapamycin, an autophagy activator, showed similar therapeutic effects to aucubin on MTX-induced enteritis. However, 3-methyladenine, an autophagy inhibitor, reversed the protective effects of aucubin. These findings prompted the hypothesis that aucubin alleviates MTX-induced enteritis by aggravating autophagy. This study might provide evidence for further investigation on the therapeutic role of aucubin in MTX-resulted enteritis.

Real-time combustion rate of wood charcoal in the heating fire basin: Direct measurement and its correlation to CO emissions.

Previous studies of solid fuel emissions in household stoves focused more on emission measurements of the overall combustion process instead of the dynamic burning rate and its connection to the emissions. This study put forward a measurement system to monitor the dynamic fuel burning rate and emission rate directly, and explored their relationships during different combustion phases. Experiments were conducted using two types of wood charcoal consumed in a small open pan (i.e. fire basin) used commonly for space heating in rural China. The measured real-time CO emission rate (ERCO), fuel burning rate (BRF), and calculated carbon burning rate (BRC) all rose and then subsided as the combustion progressed. The relationships between ERCO and BRF and between ERCO and BRC were different for the two charcoals during a phase with rising carbon content in the combusted fuel (Phase I), likely because moisture evaporation and volatile matter release were the dominant processes and the reaction was complex during this phase. ERCO and BRF or BRC had linear relationships during a phase with stable carbon content in the combusted fuel (Phase II) for the two charcoals, which may be generalized to other solid fuels, because this phase is associated to fixed carbon dominating phase which usually exist during solid fuel combustion. The study presented a novel measurement approach to the combustion properties of solid fuels. The results implied that a complex relationship between the combustion and pollutant emissions existed in Phase I, and presented the possibility of estimating the fuel burning rate based on emission measurements in Phase II, or vice versa.

The impact of cookstove operation on PM2.5 and CO emissions: A comparison of laboratory and field measurements.

Inefficient biomass combustion in traditional cookstoves generates high levels of household air pollution (HAP) that is associated with numerous adverse environmental and human health conditions. Many cookstoves have been evaluated using laboratory tests, but past studies revealed discrepancies between laboratory and field measurements. Fuel re-loading, a common operation in actual use but not required in the laboratory test, might be a contributing factor to this laboratory-field gap. In this study, we evaluated the pollutant emissions performance of a semi-gasifier cooking stove using both laboratory and field measurements. Emission factors and real-time properties of CO and PM2.5 were separately measured during the following 4 phases of a typical cooking event: lighting, stable combustion, fuel re-loading and post fuel re-loading. We quantified the CO and PM2.5 contributions to total cooking event emissions in each phase. We found over 70% lower PM2.5 emissions and 60% lower CO emissions during 3 no re-loading laboratory tests compared with all 16 field tests. Lighting generated 83.8% ±â€¯15.6% of the total PM2.5 and 39.1% ±â€¯7.8% of the total CO in laboratory tests without fuel re-loading, and 57.8% ±â€¯33.5% and 37.9% ±â€¯21.2% of the total PM2.5 and CO in field tests, respectively. On average, fuel re-loading led to 29.1% ±â€¯30.8% of PM2.5 emissions and 24.9% ±â€¯22.6% of CO emissions in 16 field tests, which also contributed to significant discrepancies between laboratory and field-based emissions. According to the ISO IWA tiered stove ratings for emissions, fuel re-loading led to at least one tier lower ranking in both laboratory and field cookstove tests. Fuel re-loading could be an important factor causing laboratory-field discrepancy of emissions, thus it could be considered in future cookstove selection and intervention projects.

A field experimental study on non-methane hydrocarbon (NMHC) emissions from a straw-returned maize cropping system.

Non-methane hydrocarbons (NMHCs) play an important role in the atmospheric environment. However, NMHC emissions from agricultural fields, especially their variations with straw return, are poorly understood. Therefore, a field study comprising two treatments, i.e., (1) S0 (straw removal) and (2) S1 (incorporation of maize straw at a rate of 9000 kg ha-1), was conducted in a straw-returned maize cropping system to characterize NMHC emissions as well as to estimate the effect of straw return on those emissions. Using a Gas Chromatography-Mass Spectrometer (GC-MS) method, 28 types of NMHCs were identified. The total NMHC emission from S0 was 2018 g ha-1, where 1-methyl-3-propyl-benzene, (1-methylethyl)-benzene, and toluene were obviously predominant, whereas the total NMHC emission from S1 was 1903 g ha-1, where 1-methyl-3-propyl-benzene, 2-methyl-pentane, and (1-methylethyl)-benzene were the main species. The results showed that straw return had opposing effects on NMHC emissions, ranging from -55.4% to 478.6%. Overall, the total NMHC emission with returned straw alone decreased by 2963 ng kg straw-1 h-1. Furthermore, NMHC fluxes had higher correlations with soil temperature than with soil moisture or pH. Notably, the higher correlations of NMHC fluxes with 10 cm soil temperature than with 5 cm soil temperature indicate that soil in the deeper layer might play a more important role in NMHC fluxes. The results also suggest that more field study is needed to accurately estimate the effect of straw return on NMHC emissions from agroecosystems and fully understand its underlying mechanism.