To assess the influences of blood sampling volumes or sites on toxicological and toxicokinetic (TK) evaluations, 4-week duration animal studies and a single-dose TK study of imipramine were conducted. In the toxicological evaluation, six-week-old Sprague-Dawley rats were divided into no blood and blood sampling groups. Fifty microliters (microsampling) or 100 μL (larger sampling) of blood/time point was collected from the jugular vein (50 μL of data was reported previously as Yokoyama et al., 2020) or the tail vein 6 to 7 times on days 1/2 and in week 4. Although no parameters were affected by the 100 μL sample from the tail vein, the 100 μL jugular vein sampling decreased the red blood cell parameters in females, possibly due to hemorrhage at the sampling site. Regarding the TK assessment, 50 μL of blood/site/time point was collected at 6 time points from the tail and jugular vein of the same male rats after single oral administration of 10 or 100 mg/kg imipramine, which was selected as a representative drug with high distribution volume. Although there were no differences in the AUC0-24hr and Cmax values between the sites, the plasma concentrations at the early time points were significantly lower from the tail vein than the jugular vein. From our studies, 50 μL of jugular and tail vein microsampling did not affect the toxicity parameters or AUC/Cmax. However, appropriate toxicity considerations and/or selection of the blood sampling site may be important in the case of larger sampling volumes or blood concentration assessment.
Acute paraquat poisoning (APP) is a serious public health problem with a high mortality rate and there is no specific antidote for APP in clinical. Early haemoperfusion (HP) treatment is effective in APP rescue. In this study, we compared the influence of routine HP and continuous HP on the survival rate and the treatment of pulmonary fibrosis in mild and moderate APP patients. Eighty-two cases of mild and moderate APP patients who were admitted to our hospital from January of 2017 to December of 2018 were selected. All patients were randomly divided into a routine haemoperfusion (HP) group (n = 40) and a continuous haemoperfusion (CHP) group (n = 42). Compared with the HP group, the 28-day survival rate of mild and moderate APP patients was elevated in the CHP group. Blood N-terminal procollagen Ш propeptide (PIIINP) levels in APP patients were positively related with paraquat (PQ) concentration (r = 0.309, P = 0.000). There were statistically significant differences in the levels of PIIINP, Collage TypeIV (CIV), transforming growth factor-beta 1 (TGF-β1), malondialdehyde (MDA), superoxide dismutase (SOD) activity and sequential organ failure assessment (SOFA) score between the two groups both on the third and seventh days after treatment, and the treatment effect of the CHP group on pulmonary fibrosis in APP patients was better than that of the HP group. In conclusion, CHP treatment had a significant therapeutic effect on mild and moderate APP patients, which could effectively improve the survival rate and relieve pulmonary fibrosis.
Manganese (Mn) poisoning may result in a neurological disorder called manganism. Although the neurotoxic mechanism of Mn is unclear, oxidative stress may be involved based on the interactions between neurotransmitter catecholamines and metals such as iron. Here, we propose a novel mechanism in which Mn oxidizes catecholamines and inhibits cellular transcription. Mn accelerated the oxidation of adrenaline (Ad) and produced adrenochrome (AdC) more effectively than iron. Furthermore, the oxidation of DNA bases increased when Ad, Mn, and iron were present. However, despite the absence of iron, cell viability decreased in the presence of AdC or Ad with Mn, which suggests there is another mechanism independent of oxidative DNA damage. AdC or preincubated Ad with Mn reduced mRNA synthesis in T7 RNA polymerase-driven transcription. RNA synthesis decreased in AdC-treated cells dose-dependently. These results show that Mn disrupts neuronal function via catecholamine oxidation-mediated transcriptional inhibition.
NOD-like receptor protein 3 (NLRP3) is involved in acute lung injury (ALI), but its exact role in phosgene-induced ALI is not clearly understood. The aim of the study is to explore the potential therapeutic effect of NLRP3 inflammasome modulation in the management of phosgene-induced ALI. ALI was induced in rats by phosgene exposure at 8.33 g/m3 for 5 min, 30 hr before intravenous injection of adenovirus-NLRP3 shRNA (Ad/NLRP3-shRNA). The histological changes in the lung were evaluated. Bronchoalveolar lavage fluid (BALF) neutrophils were counted (smear), and protein content was measured using the BCA assay. The wet/dry ratio of lung tissue (W/D) was measured. TUNEL staining for DNA damage was used to indirectly assess pyroptosis. NLRP3 inflammasome was assessed by immunohistochemistry, RT-PCR, western blotting. Cytokines were measured by ELISA. Histological analyses revealed reduced severity in phosgene-induced ALI with Ad/NLRP3-shRNA pretreatment. TUNEL staining indicated decreased pyroptosis in Psg-Ad/NLRP3-shRNA rats. Decreased mRNA and protein levels of NLRP3 and caspase-1 (all P < 0.05), but not ASC (P > 0.05), were found in Psg-Ad/NLRP3-shRNA rats. Immunohistochemistry revealed that Ad/NLRP3-shRNA pretreatment inhibited NLRP3 inflammasome activation. Reduced level of pro-inflammatory interleukin (IL)-1β, IL-18, IL-33, and tumor necrosis factor (TNF)-α (all P < 0.05), but not of anti-inflammatory IL-4 and IL-10 (all P > 0.05), were found in serum and BALF from Ad/NLRP3-shRNA rats. NLRP3 gene silencing exerts beneficial effects on phosgene-induced lung injury by inhibiting NLRP3 inflammasome activation and pro-inflammatory factors, but not anti-inflammatory factors. Disruption of NLRP3 inflammasome activation might be used as a therapeutic modality for the treatment of phosgene-induced ALI.
Bisphenol A (BPA), an endocrine disruptor with estrogenic effects, is widely used as a raw material for manufacturing polycarbonate plastic and epoxy resins. Prenatal and postnatal exposure to BPA affects brain morphogenesis. However, the effects of prenatal and postnatal BPA exposure on postnatal neurogenesis in mice are poorly understood. In this study, we developed a mouse model of prenatal and postnatal BPA exposure and analyzed its effects on hippocampal neurogenesis. The hippocampal dentate gyrus is vulnerable to chemical exposure, as neurogenesis continues in this region even after birth. Our results showed that in mice, prenatal and postnatal BPA exposure decreased the number of type-1, 2a, 2b, and 3 neural progenitor cells, as well as in granule cells, in the hippocampal dentate gyrus on postnatal days 16 and 70. The effect of prenatal and postnatal BPA exposure on neural progenitors were affected at all differentiation stages. In addition, prenatal and postnatal BPA exposure affects the maintenance of long-term memory on postnatal day 70. Our results suggest that neurodevelopmental toxicity due to prenatal and postnatal BPA exposure might affect postnatal morphogenesis and functional development of the hippocampal dentate gyrus.
Inhalation of silica particles leads to pulmonary inflammatory responses. Clara cell protein 16 (CC16) has been reported to played a protective role in inflammatory lung diseases. However, its role on silica particles-induced inflammation has not been fully clarified. In this study, THP-1 macrophages were exposed to 75 μg/cm2 silica particles with or without 2 μg/mL exogenous CC16 (recombinant CC16, rCC16) for 24 hr. The production of inflammatory cytokines, including interleukin (IL)-1β, tumor necrosis factor (TNF)-α and IL-6, in the cell supernatants of different groups was detected through ELISA kits and real-time RT-PCR, respectively. The nuclear translocation of nuclear factor (NF)-κB, protein levels of pro-IL-1β, the nucleotide-binding domain-like receptor protein 3 (NLRP3) and caspase-1 were evaluated via immunofluorescence or western blot. Results showed that, at 75 μg/cm2 silica particle concentration, the treatment of rCC16 significantly decreased IL-1β, TNF-α and IL-6 protein release and mRNA levels in THP-1 macrophages. Compared to those only exposed to silica particles, THP-1 macrophages exposed to both silica particles and rCC16 showed significantly lower nuclear levels and higher cytosol levels of NF-κB p65, as well as lower co-localization coefficients through immunofluorescence. Additionally, the administration of rCC16 significantly attenuated the increase of pro-IL-1β, NLRP3 and caspase-1 levels induced by silica particle exposure. Our results suggested that exogenous CC16 could inhibit silica particles-induced inflammation in THP-1 macrophages, mainly through suppressing NF-κB pathway and caspase-1 activation.