{'fraction_non_alphanumeric': 0.02605674580196873, 'fraction_numerical': 0.010422698320787493, 'mean_word_length': 5.23826714801444, 'pattern_counts': {'":': 0, '<': 0, '<?xml version=': 0, '>': 0, 'https://': 0, 'lorem ipsum': 0, 'www.': 0, 'xml': 0}, 'pii_count': 0, 'substrings_counts': 0, 'word_list_counts': {'cursed_substrings.json': 0, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
Are titanium dioxide nanoparticles toxic to the cerebral cortex of rats? A histological and immunohistochemical study

Background Titanium dioxide (TiO2) nanoparticles (NPs) are used extensively in many commercial products, including paints, cosmetics, plastics, paper, and food. Therefore, widespread exposure may occur during both manufacturing and application. Their potential risk for the central nervous system has elicited much concern recently. Aim The aim of this work was to evaluate the toxicity of TiO2 NPs on the cerebral cortex of adult male albino rats. Materials and methods Thirty adult male albino rats were divided equally into three groups. Group I served as the control group; group II consisted of animals that received a low dose of TiO2 (600 mg/kg/day for 5 consecutive days); and group III consisted of animals that received a high dose of TiO2 (1 g/kg/day for 5 consecutive days). After 4 weeks from the last dose, the rats were sacrificed and the posterior parietal lobe of the cerebral cortex was processed and examined using histological and immunohistochemical techniques. Results The results revealed that a low dose of TiO2 induced minimal histological changes. A few pyramidal cells showed darkly stained hyperchromatic nuclei. The high-dose TiO2 group showed marked histological changes in pyramidal cells; some cells appeared with deeply stained nuclei, with significant increase (P⩽0.05) in caspase-3 reaction compared with the control group. Electron microscope revealed electron-lucent vacuoles in the cytoplasm, disrupted mitochondria, and dilated cisterns of rough endoplasmic reticulum. Conclusion High doses of TiO2 NPs should be avoided because of its cerebral cortex toxicity in rats.