BACKGROUND: Methylmercury (MeHg) causes damage specifically in cerebrocortical neurons, but not in hippocampal neurons. In our previous studies using cultured neurons, we found that brain-derived neurotrophic factor (BDNF), which is prominently present in hippocampal neurons, plays a key role in resistance to MeHg neurotoxicity. Our findings, combined with recent findings that moderate exercise increases BDNF in the brain, led us to hypothesize that moderate exercise protects against MeHg-induced neurotoxicity by inducing BDNF expression. METHODS: C57 black 6NJcl (C57BL/6NJcl) male mice were used to evaluate the effects of treadmill exercise (a moderate exercise) on the neurotoxicity of MeHg exposure at 1.5 mg/kg/day. The effects of treadmill exercise on MeHg neurotoxicity were evaluated through neurobehavioral, neuropathological, and biochemical analyses using brain tissue, blood, and muscle tissue. RESULTS: Treadmill exercise had a significant inhibitory effect on the neurological symptoms associated with apoptotic neuronal death and subsequent cerebrocortical neuron loss induced by MeHg exposure. In the cerebral cortex, treadmill exercise significantly increased BDNF levels and activated the neuroprotective-related BDNF-tropomyosin receptor kinase (Trk) B and p44/42 mitogen-activated protein kinase (MAPK) pathways along with significantly suppressing the neuronal cell death-associated p38 MAPK pathway. Furthermore, treadmill exercise significantly increased fibronectin type III domain containing 5 (FNDC5) expression in the muscle tissue and elevated ed the concentration of its metabolite, irisin, in the blood. CONCLUSIONS These results suggest that treadmill exercise increases BDNF in the brain and suppresses neurotoxic pathways, ultimately protecting against MeHg neurotoxicity. Moreover, the increase of BDNF in the brain may be attributed to the exercise-induced increased expression of FNDC5 in muscle tissue from where it is released into the blood as irisin and finally transferred into the brain and promoted BDNF production.
Animals ; Brain-Derived Neurotrophic Factor/genetics* ; Methylmercury Compounds/toxicity* ; Male ; Mice ; Mice, Inbred C57BL ; Physical Conditioning, Animal ; Brain/drug effects* ; Neurotoxicity Syndromes/prevention & control*

The study explored the pathological mechanism of doxorubicin chemotherapy-induced neurotoxicity and the intervention methods of traditional Chinese medicine. BALB/c mice were selected to establish tumor-bearing mouse models by orthotopic injection of 4T1 triple-negative breast cancer cells. After randomization, the mice were treated with doxorubicin chemotherapy or doxorubicin chemotherapy + Kaixin San(KXS). The lesions in the prefrontal cortex of mice were observed by pathological examination, and the lesion information was obtained by long non-coding RNA sequencing. The occurrence of lesions was determined by Western blot and biochemical indicators. In addition, neuroblastoma cells and microglia cells were used to construct in vitro models, and drug-containing serum and p-AMPK dephosphorylation inhibitors were used to further verify the accuracy of animal experiments. Pathological results showed that KXS could alleviate doxorubicin-induced neuronal degeneration in the prefrontal cortex. The long non-coding RNA sequencing suggested that neuronal degeneration and the intervention process of KXS were related to ferroptosis, immune diseases, AMPK signaling pathway, etc. Western blot and biochemical indicators confirmed that this process was directly related to the activation of the AMPK/HIF-1α/ACSL4 signaling pathway to alleviate ferroptosis of neurons and immune response of glial cells. In conclusion, KXS could alleviate doxorubicin-induced neurotoxicity by activating the AMPK signaling pathway and reducing the ferroptosis of neurons and immune response of glial cells.
Animals ; Doxorubicin/toxicity* ; Mice ; AMP-Activated Protein Kinases/genetics* ; Signal Transduction/drug effects* ; Mice, Inbred BALB C ; Drugs, Chinese Herbal/administration & dosage* ; Female ; Humans ; Cell Line, Tumor ; Neurotoxicity Syndromes/genetics*

OBJECTIVETo investigate acrylamide (ACR)-induced subacute neurotoxic effects on the central nervous system (CNS) at the synapse level in rats.

METHODSThirty-six Sprague Dawley (SD) rats were randomized into three groups, (1) a 30 mg/kg ACR-treated group, (2) a 50 mg/kg ACR-treated group, and (3) a normal saline (NS)-treated control group. Body weight and neurological changes were recorded each day. At the end of the test, cerebral cortex and cerebellum tissues were harvested and viewed using light and electron microscopy. Additionally, the expression of Synapsin I and P-Synapsin I in the cerebral cortex and cerebellum were investigated.

RESULTSThe 50 mg/kg ACR-treated rats showed a significant reduction in body weight compared with untreated individuals (P < 0.05). Rats exposed to ACR showed a significant increase in gait scores compared with the NS control group (P < 0.05). Histological examination indicated neuronal structural damage in the 50 mg/kg ACR treatment group. The active zone distance (AZD) and the nearest neighbor distance (NND) of synaptic vesicles in the cerebral cortex and cerebellum were increased in both the 30 mg/kg and 50 mg/kg ACR treatment groups. The ratio of the distribution of synaptic vesicles in the readily releasable pool (RRP) was decreased. Furthermore, the expression levels of Synapsin I and P-Synapsin I in the cerebral cortex and cerebellum were decreased in both the 30 mg/kg and 50 mg/kg ACR treatment groups.

CONCLUSIONSubacute ACR exposure contributes to neuropathy in the rat CNS. Functional damage of synaptic proteins and vesicles may be a mechanism of ACR neurotoxicity.

Acrylamide ; toxicity ; Animals ; Cerebellum ; cytology ; drug effects ; Cerebral Cortex ; cytology ; drug effects ; Drug Administration Schedule ; Gait ; Gene Expression Regulation ; drug effects ; Male ; Neurons ; drug effects ; Neurotoxicity Syndromes ; pathology ; Rats ; Rats, Sprague-Dawley ; Synapses ; drug effects ; Synapsins ; genetics ; metabolism ; Synaptic Vesicles ; drug effects ; physiology ; Weight Loss ; drug effects

OBJECTIVETo investigate the relationship between mRNA expression of manganese superoxide dismutase (MnSOD) and manganese neurotoxicity.

METHODSThirty-one patients with occupational chronic manganese poisoning (case group), as well as 31 controls exposed to the same condition (control group), were included in the study. Whole blood RNA was extracted, and the mRNA expression of MnSOD was measured by RT-PCR; the two groups were compared in terms of the mRNA expression of MnSOD. PC12 cells were treated with 0, 100, 200, 400, 600, 800, and 1000 ümol/L MnCl₂ for l, 2, 3, and 4 d; the cell viability was determined by MTT assay, and the mRNA expression of MnSOD was measured by RT-PCR.

RESULTSThe case group had significantly lower mRNA expression of MnSOD than the control group (0.390 ± 0.080 vs 0.582 ± 0.219, P < 0.05). MnCl2 had a toxic effect on PC12 cells; the concentration of MnCl₂ was positively correlated with the toxic effect but negatively correlated with the mRNA expression of MnSOD.

CONCLUSIONMnSOD mRNA may be involved in the manganese-induced damage of nerve cells. It is hypothesized that high mRNA expression of MnSOD may play an inhibitory effect on manganese neurotoxicity.

Adult ; Animals ; Female ; Gene Expression ; Humans ; Male ; Manganese Poisoning ; genetics ; Middle Aged ; Neurotoxicity Syndromes ; genetics ; PC12 Cells ; RNA, Messenger ; genetics ; Rats ; Superoxide Dismutase ; genetics

3,4-Methylenedioxymethamphetamine (MDMA) is a substituted amphetamine with stimulating and hallucinogenic properties. Since MDMA induces "ecstasy" it is extensively used as a "recreational" drug. It has been well established that MDMA is neurotoxic and can result in long-term degeneration of cerebral 5-hydroxytryptamine (5-HT) nerve terminals in many species. The present study was undertaken to investigate the long-term neurotoxic effects of MDMA on cortical and hippocampal structures, by repeatedly administering MDMA in short time. Male Wistar rats were randomly assigned to control group and MDMA-treated group. MDMA (10 mg/kg) was administered to rats of MDMA-treated group, once per hour, total 40 mg/kg; rats of control group were treated with the same volume of saline. Thirty-two weeks after administering MDMA, the expression of serotonin transporter (SERT) mRNA and diazepam binding inhibitor (DBI) mRNA was detected by in situ hybridization. The expression of glial fibrillary acidic protein (GFAP) was detected by immunohistochemistry, and the degeneration of nerve terminals was demonstrated by Bielschowsky and Glee Marsland silver staining. The results showed that the expression of SERT mRNA in hippocampus decreased by 31.96%, while expression of DBI mRNA in neocortex increased by 40.51%, compared with the control group (P<0.05). The expression of GFAP in the brain tissue increased (P<0.05), while significant reduction of the nerve terminals in neocortex was demonstrated by silver staining, compared with the control group. These results suggest that the neurotoxicity of MDMA results in sustained cortical and hippocampal structural changes, which in turn result in disorder of the brain functions.
Animals ; Cerebral Cortex ; pathology ; physiopathology ; Diazepam Binding Inhibitor ; genetics ; metabolism ; Hippocampus ; pathology ; physiopathology ; Male ; N-Methyl-3,4-methylenedioxyamphetamine ; toxicity ; Neurotoxicity Syndromes ; etiology ; pathology ; physiopathology ; RNA, Messenger ; genetics ; metabolism ; Rats ; Rats, Wistar ; Serotonin Plasma Membrane Transport Proteins ; genetics ; metabolism