Effects of acute exposure to Al2O3-NPs (α and γ) and white noise and their combination on cochlea structure and function in Wistar rats.

Hearing loss induced by noise and combinations of factors is a common occupational disease among workers. This study aimed to investigate the impact of acute exposure to white noise and Al2O3 NPs, alone and in combination, on changes in the hearing and structural functions of the cochlea in rats. Thirty-six rats were randomly assigned to one of six groups: Control, acute exposure to white noise, exposure to γ-Al2O3 NPs, exposure to noise plus γ-Al2O3 NPs, exposure to α-Al2O3 NPs, and exposure to the combination of noise plus α-Al2O3 NPs. TTS and PTS were examined using DPOAE, while oxidative index (MDA, GSH-Px), gene expression (NOX3, TGF-ß, CYP1A1), protein expression (ß-Tubulin, Myosin VII), and histopathological changes were examined in the cochlea. The morphology of Al2O3 NPs was examined by TEM. The results of the DPOAE test showed a significant increase in TTS in all groups and an increase in PTS in the groups exposed to noise, γ-Al2O3 NPs, and a combination of noise plus Al2O3 NPs (P < 0.05). In the group exposed to white noise plus Al2O3 NPs, the MDA levels increased, the level of GSH-Px decreased, and the expression percentage of ß-Tubulin and Myosin VII decreased, while the expression of NOX3, TGF-ß, and CYP1A1 (except for the α-Al2O3 NPs group) significantly increased (P < 0.05). Histopathological changes of the cochlea indicated damage to hair and ganglion cells, which was more severe in the combined exposure group. The combined and independent exposure to white noise and Al2O3 NPs damaged hair and ganglion cells for high-frequency perception, affecting the function and structure of the cochlea and leading to TTS and PTS.

Toxicity of Hydrogen Sulfide on Rat Brain Neurons.

Hydrogen sulfide (H2S) is a toxic compound known as a member of the gasotransmitter family. H2S has the ability to inhibit the cytochrome c oxidase enzyme in the mitochondrial respiratory chain. Mitochondria play an important role in energy production and the brain needs energy for normal function. Mitochondrial dysfunction is associated with neurodegenerative diseases. This study investigated the mechanisms of cytotoxicity induced by H2S in brain neurons. thioacetamide has been used to produce H2S in water solutions. The results of the study showed that thioacetamide at concentrations of 116, 232 and 464 µg/ml was able to increase the level of reactive oxygen species (ROS), collapse in mitochondrial membrane potential (MMP), damage to the lysosomal membrane, increase in the level of oxidized glutathione (GSSG) and decrease in the level of reduced glutathione (GSH) in brain neurons. The results of the study suggested that H2S causes damage to mitochondria and lysosomes in brain neurons that could be associated with neurodegenerative diseases.

Reducing the risk of death induced by aluminum phosphide poisoning: The new therapies.

Numerous people suffer from accidental or deliberate exposure to different pesticides when poisoning with aluminum phosphate (AlP) is increasing in the eastern countries. Aluminum phosphate is a conventional insecticide that quickly reacts with water or the moistures in the atmosphere and produces fatal phosphine gas, which absorbs quickly by the body. Oral consumption or inhalation of AlP leads to excessive reaction of the body such as fatigue, vomiting, fever, palpitation, vasodilatory shock, increasing blood pressure, cardiac dysfunction, pulmonary congestion, shortness of breath, and death. The garlic smell from the patient's mouth or exhale is one of the methods to recognize the positioning. Due to the lack of individual antidotes, several supportive treatments are required. The present study focused on the available and new therapies that help reduce the effect of AlP poisoning and the mortality rate. The therapies are divided into the antioxidant-related agent and the other agents. The impacts of each agent on the experimental cases are reported.