Effects of Photobiomodulation on Oral Mucositis: Visualization and Analysis of Knowledge.

This review article mapped and analyzed the most cited articles on the association of photobiomodulation (PBM) with oral mucositis (OM) and the evolution of clinical protocols in the area. A comprehensive search was performed on the Web of Science Core Collection (WoS-CC) database, leading to the extraction of information such as title, authors, abstract, journal name, number, average of citations, study design, year of publication, institutions, continents, countries, type of laser used, irradiated anatomical points, primary anti-cancer therapy, and laser parameters. Among those, clinical trials and literature reviews were the most common study designs. The main type of laser used was the InGaAlP diode, with a wavelength ranging from 630-660 nm, power going in 40-100 mW, and energy density ranging from 0.375-22 J/cm2. As for the anatomical sites irradiated by PBM, the cheek mucosa, upper and lower lips, lateral tongue, and bottom of the mouth stood out. This analysis highlights an increasing interest in PBM as a supportive treatment in cases of OM, as well as the evolution of the technique, types of laser devices, and protocols used.

Evaluation of Cerebellar Function and Integrity of Adult Rats After Long-Term Exposure to Aluminum at Equivalent Urban Region Consumption Concentrations.

High amounts of aluminum (Al) are found in soil and water. It is highly bioavailable, which makes it an important agent of environmental imbalance. Moreover, Al is considered a neurotoxic agent that is associated with several neurodegenerative diseases. Thus, this study investigated the effects of long-term Al chloride (AlCl3) exposure on motor behavior, oxidative biochemistry, and cerebellar tissue parameters. For this, adult Wistar rats were divided into three groups: Al-D1 (8.3 mg kg-1 day-1), Al-D2 (5.2 mg kg-1 day-1), and control (distilled water); all groups were orally exposed for 60 days by intragastric gavage. After the exposure period, animals performed the open field, elevated plus maze, rotarod, and beam walking tests. Then, the blood and cerebellum were collected to evaluate Al levels and biochemical and morphological analyses, respectively. Our results demonstrate that animals exposed to Al doses presented a higher Al level in the blood. In the spontaneous locomotor activity, Al exposure groups had traveled a lower total distance when compared with the control group. There was no statistically significant difference (p > 0.05) between exposed and control groups when anxiogenic profile, forced locomotion, fine motor coordination/balance, pro-oxidative parameter, and density Purkinje cells were compared. Thus, aluminum exposure in equivalent doses to human consumption in urban regions did not promote significant changes in the cerebellum or motor parameters.

Preclinical evidences of aluminum-induced neurotoxicity in hippocampus and pre-frontal cortex of rats exposed to low doses.

Aluminum (Al) is a neurotoxicant agent implicated in several behavioral, neuropathological and neurochemical changes associated with cognitive impairments. Nevertheless, mechanisms of damage and safety concentrations are still very discussed. Thus, the main purpose of this study was to investigate whether two aluminum low doses were able to produce deleterious effects on cognition of adult rats, including oxidative stress in hippocampus and prefrontal cortex, two important areas for cognition. For this, thirty adult Wistar rats were divided into three groups: Al1 (8.3 mg/kg/day), Al2 (32 mg/kg/day) and Control (Ultrapure Water), in which all three groups received their solutions containing or not AlCl3 by intragastric gavage for 60 days. After the experimental period, the short- and long-term memories were assessed by the object recognition test and step-down inhibitory avoidance. After euthanizing, prefrontal cortex and hippocampus samples were dissected for Al levels measurement and evaluation of oxidative biochemistry. Only Al2 increased Al levels in hippocampal parenchyma significantly; both concentrations did not impair short-term memory, while long-term memory was affected in Al1 and Al2. In addition, oxidative stress was observed in prefrontal and hippocampus in Al1 and Al2. Our results indicate that, in a translational perspective, humans are subjected to deleterious effects of Al over cognition even when exposed to low concentrations, by triggering oxidative stress and poor long-term memory performance.

Blood Oxidative Stress Modulates Alveolar Bone Loss in Chronically Stressed Rats.

We aimed to investigate the effects of chronic stress (CS) on experimental periodontitis (EP) in rats. For this, 28 Wistar rats were divided into four groups: control, ligature-induced experimental periodontitis (EP), chronic stress (CS; by physical restraint model) and CS+EP (association of chronic stress and ligature-induced periodontitis). The experimental period lasted 30 days, including exposure to CS every day and ligature was performed on the 15th experimental day. After 30 days, the animals were submitted to the behavioral test of the elevated plus maze (EPM). Next, rats were euthanized for blood and mandible collection in order to evaluate the oxidative biochemistry (by nitric oxide (NO), reduced-glutathione activity (GSH), and thiobarbituric acid reactive substance levels (TBARS)) and alveolar bone characterization (by morphometric, micro-CT, and immunohistochemistry), respectively. The behavioral parameters evaluated in EPM indicated higher anxiogenic activity in the CS and CS+EP, groups, which is a behavioral reflex of CS. The results showed that CS was able to change the blood oxidative biochemistry in CS and CS+EP groups, decrease GSH activity in the blood, and increase the NO and TBARS concentrations. Thus, CS induces oxidative blood imbalance, which can potentialize or generate morphological, structural, and metabolic damages to the alveolar bone.