Sodium para-aminosalicylic acid attenuates combined manganese/iron-induced cortical synaptic damage in rats.

We established experimental models of manganese (Mn) and iron (Fe) exposure in vitro and in vivo, and addressed the effects of manganese and iron combined exposure on the synaptic function of pheochromocytoma derived cell line 12 (PC12) cells and rat cortex, respectively. We investigated the protective effect of sodium para-aminosalicylate (PAS-Na) on manganese and iron combined neurotoxicity, providing a scientific basis for the prevention and treatment of ferromanganese combined neurotoxicity. Western blot and reverse transcription-quantitative polymerase chain reaction (RT-qPCR) were performed to detect the expression levels of protein and mRNA related to synaptic damage. Y-maze novelty test and balance beam test were used to evaluate the motor and cognitive function of rats. Haematoxylin and eosin (H&E) and Nissl staining were performed to observe the cortical damage of rats. The results showed that the combined exposure of Mn and Fe in rats led to a synergistic effect, attenuating growth and development, and altering learning and memory as well as motor function. The combination of Mn and Fe also caused damage to the synaptic structure of PC12 cells, which is manifested as swelling of dendrites and axon terminals, and even lead to cell death. PAS-Na displayed some antagonistic effects against the Mn- and Fe-induced synaptic structural damage, growth, learning and memory impairment.

Clinical case analysis of 32 children aged 0-6 years with lead poisoning in Nanning, China.

Lead is one of the heavy metals that is toxic and widely distributed in the environment, and children are more sensitive to the toxic effects of lead because the blood-brain barrier and immune system are not yet well developed. The objective of the study was to investigate the clinical characteristics of lead poisoning in children aged 0∼6 years in a hospital in Guangxi, and to provide scientific basis for the prevention and treatment of lead poisoning. We collected and analyzed the clinical data of 32 children with lead poisoning admitted to a hospital in Guangxi from 2010 to 2018. The results showed that most of the 32 cases presented with hyperactivity, irritability, poor appetite, abdominal pain, diarrhea, or constipation. The hemoglobin (HGB), mean corpusular volume (MCV), mean corpuscular hemoglobin (MCH), and hematocrit (HCT) of the lead-poisoned children were all decreased to different degrees and were below normal acceptable levels. Urinary ß2-microglobulin was increased. Blood lead levels (BLL) decreased significantly after intravenous injection of the lead chelator, calcium disodium edetate (CaNa2-EDTA). In addition, HGB returned to normal levels, while MCV, MCH, and HCT increased but remained below normal levels. Urinary ß2-microglobulin was reduced to normal levels. Therefore, in this cohort of children, the high-risk factors for lead poisoning are mainly Chinese medicines, such as baby powder. In conclusion, lead poisoning caused neurological damage and behavioral changes in children and decreased erythrocyte parameters, leading to digestive symptoms and renal impairment, which can be attenuated by CaNa2-EDTA treatment.

Effects of Manganese and Iron, Alone or in Combination, on Apoptosis in BV2 Cells.

The aim of study was to address the effects of manganese and iron, alone and in combination, on apoptosis of BV2 microglia cells, and to determine if combined exposure to these metals augments their individual toxicity. We used a murine microglial BV2 cell line. Cell cytotoxicity was analyzed by propidium iodide (PI) exclusion assay. Cell ROS production was analyzed by 2', 7'-dichlorofluorescin diacetate (DCFH-DA) probe staining. Pro-inflammatory cytokine production was monitored by ELISA. Cell apoptosis was analyzed by PE Annexin V/7-AAD staining. Mitochondrial membrane integrity was analyzed by flow cytometry. We used immunoblotting to analyze the effect of manganese, iron alone, or their combined exposure on the activation of caspase9, P53, Bax, and Bcl2 apoptosis signaling pathways. Caspase3 activity was determined using a Colorimetric. Manganese, iron, and their combined exposure for 24 h induced the activation of BV2 microglia cells and increased ROS production and the expression of the inflammatory cytokines, IL-1ß and TNF-α. And we also found that the apoptosis rate increased, mitochondrial membrane potential decreased, apoptosis-related proteins caspase9, P53, Bax, and Bcl2 expression increased, and caspase3 activity increased. Furthermore, we found that combined manganese-iron cytotoxicity was lower than that induced by manganese exposure alone. Manganese, iron alone, or their combination exposure can induce apoptosis in glial cells. Iron can reduce the toxicity of manganese, and there is an antagonistic effect between manganese and iron.

Protective Effects of Sodium Para-Aminosalicylic Acid on Lead and Cadmium Co-Exposure in SH-SY5Y Cells.

BACKGROUND: Combined exposure to lead and cadmium is common in occupational environments. However, the effects of co-exposure to Pb-Cd on neurotoxicity have not been fully clarified. Sodium para-aminosalicylic acid (PAS-Na) has previously been shown to protect neurons from Pb-induced toxicity. This study aimed to investigate the beneficial effect of PAS-Na against co-exposure to Pb-Cd-induced neurodegeneration in SH-SY5Y cells. METHODS: The MTT assay was used to detect the effects of Pb and Cd alone, or in combination, on SH-SY5Y cell survival. The effects of Pb and Cd alone or in combination on oxidative stress were assessed by reactive oxygen species (ROS) level. Nrf2, the master switch for antioxidant responses, was detected by immunofluorescence. Protein expression levels of PI3K, Akt, p-Akt, Nrf2 and HO-1 were determined by Western blot analysis. RESULTS: MTT assay results established that the survival rate of SH-SY5Y cells was not significantly affected by exposure to 1 µmol/L lead, 0.25 µmol/L cadmium, and 1-fold Pb-Cd mixture (1 µmol/L Pb + 0.25 µmol/L Cd), while 10-fold Pb-Cd combined exposure (10 µmol/L Pb + 2.5 µmol/L Cd) significantly reduced the survival rate of SH-SY5Y cells. Combined Pb-Cd exposure significantly increased intracellular ROS levels, and N-Acetyl-L-cysteine (NAC) treatment in the 10 µmol/L Pb + 2.5 µmol/L Cd group significantly decreased ROS expression levels, attenuating the levels of oxidative stress. Protein expression of PI3K and p-Akt significantly decreased in the 10 µmol/L Pb + 2.5 µmol/L Cd group, while the expression of PI3K and p-Akt protein increased after PAS-Na intervention. Immunofluorescence analysis showed that levels of Nrf2 in the nucleus increased in the 10 µmol/L Pb + 2.5 µmol/L Cd group, along with Nrf2 protein levels, suggesting that Nrf2 was translocated from the cytoplasm into the nucleus upon combined Pb-Cd exposure. In addition, HO-1 protein expression level, a downstream gene product of Nrf2, was increased. In response to NAC intervention, HO-1 protein expression levels significantly decreased. PAS-Na had the same intervention effect as NAC. CONCLUSION: Combined exposure to Pb-Cd induced oxidative stress and cytotoxicity in SH-SY5Y cells. PAS-Na displayed antagonistic effects on neurodegenerative changes induced by combined Pb-Cd exposure; hence, it may afford a novel treatment modality for exposure to these metals.

Sodium Para-Aminosalicylic Acid Modulates Autophagy to Lessen Lead-Induced Neurodegeneration in Rat Cortex.

Lead (Pb) is a common heavy metal contaminant in the environment, and it may perturb autophagy and cause neurodegeneration. Although sodium para-aminosalicylic (PAS-Na) has been shown to protect the brain from lead-induced toxicity, the mechanisms associated with its efficacy have yet to be fully understood. In this study, we evaluated the efficacy of PAS-Na in attenuating the neurotoxic effects of lead, as well as the specific mechanisms that mediate such protection. Lead exposure resulted in weight loss and injury to the liver and kidney, and PAS-Na had a protective effect against this damage. Both short-term and subchronic lead exposure impaired learning ability, and this effect was reversed by PAS-Na intervention. Lead exposure also perturbed autophagic processes through the modulation of autophagy-related factors. Short-term lead exposure downregulated LC3 and beclin1 and upregulated the expression of p62; subchronic lead exposure upregulated the expression of LC3, beclin1, and P62. It follows that PAS-Na had an antagonistic effect on the activation of the above autophagy-related factors. Overall, our novel findings suggest that PAS-Na can protect the rat cortex from lead-induced toxicity by regulating autophagic processes. (1) Short-term lead exposure inhibits autophagy, whereas subchronic lead exposure promotes autophagy. (2) PAS-NA ameliorated the abnormal process of lead-induced autophagy, which had a protective effect on the cerebral cortex.

Sodium para-aminosalicylic acid ameliorates brain neuroinflammation and behavioral deficits in juvenile lead-exposed rats by modulating MAPK signaling pathway and alpha-synuclein.

Lead (Pb) is a developmental neurotoxin that can disrupt brain development and damage the brain regions responsible for executive function, behavioral regulation and fine motor control. Sodium para-aminosalicylic acid (PAS-Na) is a non-steroidal anti-inflammatory drug that can cross the blood-brain barrier. The purpose of this study was to examine the effects of juvenile rat Pb exposure on behavioral changes and brain inflammation, and the efficacy of PAS-Na in ameliorating these effects. The results showed that Pb exposure during the juvenile period (from weaning to adult period) delayed rats' growth development and impaired their motor learning. Pb exposure not only increased Pb concentrations in several brain regions (including hippocampus, striatum and substantia nigra), but also disrupted metal-homeostasis in the brain, as higher levels of iron (Fe) and calcium (Ca) were observed in the substantia nigra. Moreover, Pb activated the MAPK pathway and increased levels of inflammatory factors such as IL-1ß, TNF-α and IL-6 in the hippocampus, striatum and substantia nigra. Furthermore, Pb increased the levels of alpha-synuclein (α-syn) in these brain sites. PAS-Na improved the motor deficits and brain inflammation in the Pb-exposed rats. Moreover, the elevated Pb, Fe and Ca concentrations in the brain were significantly reduced by PAS-Na, which contains amino, carboxyl and hydroxyl functional groups, suggesting that it may act as a chelator of brain metals. In addition, PAS-Na inhibited the Pb-induced MAPK pathway activation and α-syn accumulation in the same brain regions. Taken together, our novel study suggest that PAS-Na shows efficacy in improving the Pb-induced behavioral changes in rats by inhibiting MAPK-dependent inflammatory pathways and reducing α-syn accumulation.

Sodium Para-aminosalicylic Acid Inhibits Lead-Induced Neuroinflammation in Brain Cortex of Rats by Modulating SIRT1/HMGB1/NF-κB Pathway.

Lead (Pb) is considered to be a major environmental pollutant and occupational health hazard worldwide which may lead to neuroinflammation. However, an effective treatment for Pb-induced neuroinflammation remains elusive. The aim of this study was to investigate the mechanisms of Pb-induced neuroinflammation, and the therapeutic effect of sodium para-aminosalicylic acid (PAS-Na, a non-steroidal anti-inflammatory drug) in rat cerebral cortex. The results indicated that Pb exposure induced pathological damage in cerebral cortex, accompanied by increased levels of inflammatory factors tumor necrosis factor-alpha (TNF-α) and interleukin-1 beta (IL-1ß). Moreover, Pb decreased the expression of silencing information regulator 2 related enzyme 1 (SIRT1) and brain-derived neurotrophic factor (BDNF), and increased the levels of high mobile group box 1 (HMGB1) expression and p65 nuclear factor-κB (NF-κB) phosphorylation. PAS-Na treatment ameliorated Pb-induced histopathological changes in rat cerebral cortex. Moreover, PAS-Na reduced the Pb-induced increase of TNF-α and IL-1ß levels concomitant with a significant increase in SIRT1 and BDNF levels, and a decrease in HMGB1 and the phosphorylation of p65 NF-κB expression. Thus, PAS-Na may exert anti-inflammatory effects by mediating the SIRT1/HMGB1/NF-κB pathway and BDNF expression. In conclusion, in this novel study PAS-Na was shown to possess an anti-inflammatory effect on cortical neuroinflammation, establishing its efficacy as a potential treatment for Pb exposures.