Evaluation of photobiomodulation therapy (117 and 90s) on pain, regeneration, and epigenetic factors (HDAC 2, DNMT3a) expression following spinal cord injury in a rat model.

BACKGROUND: Photobiomodulation therapy (PBMT), due to its anti-inflammatory, analgesic effects, and most importantly as a non-invasive procedure, has currently gained a special setting in pain relief and the treatment of Spinal cord injuries (SCI). However, the mechanism of action of the PBM is not yet completely understood. METHODS: In this study, SCI is induced by an aneurysm clip, and PBM therapy was applied by a continuous-wave (CW) laser with a wavelength of 660 nm. Adult male rats were divided into four groups: Control, SCI, SCI + PBMT 90s, and SCI + PBMT 117s. After 7 weeks, hyperalgesia, allodynia, and functional recovery were assessed. Fibroblasts infiltrating the spinal cord were counted after H&E staining. The expression of epigenetic factors (HDAC2, DNMT3a), protein relevant for pain (GAD65), and astrocytes marker (GFAP) after 4 weeks of daily PBMT (90 and 117s) was probed by western blotting. RESULTS: Both PBMTs (90 and 117s) significantly improved the pain and ability to move and fibroblast invasion was reduced. SCI + PBMT 90s, increased GAD65, HDAC2, and DNMT3a expression. However, PBMT 117s decreased GFAP, HDAC2, and DNMT3a. CONCLUSION: PBMT 90 and 117s improved the pain, and functional recovery equally. The regulation of epigenetic mechanisms appears to be a significant effect of PBMT117s, which emphasizes on impact of radiation duration and accumulative energy.

Public ingestion exposure to 226Ra in Ramsar, Iran.

Ramsar, in the north of Iran by the Caspian Sea, has been known for the highest natural radiation background on Earth due to the local geology and hydrogeology. The residents and visitors use the hot springs that distribute the natural radionuclides especially 226Ra and its decay products in the areas. Many studies have been undertaken to measure the absorbed dose rate in Ramsar's air, however, no survey has been done to assess public internal exposure from ingestion of natural radionuclides, such as, a broad survey for 226Ra was conducted in foodstuffs and drinking water. This study presents the results of public annual activity intake (Bq) and effective dose (µSv) from ingestion of 226Ra in foodstuffs and drinking water in Ramsar city. The total mean annual intake for adults was found to be 24.8 Bq. The annual average effective dose due to ingestion exposure to 226Ra was found to be 6.9 µSv for adults that were slightly more than the estimated global averages reported by UNSCEAR, 2000 (6.3 µSv). The contribution of drinking water and foodstuffs represent respectively about 30% and 70% of the total mean annual effective dose due to 226Ra. The highest effective dose from ingestion of 226Ra for adults was estimated to be 80.6 µSv y-1. Based on the results of this study, even with the largest 226Ra value in our survey, maximum annual effective dose due to consumption of foodstuffs and drinking water for children was 164.2 µ b Sv y-1.

Radioactivity levels in the mostly local foodstuff consumed by residents of the high level natural radiation areas of Ramsar, Iran.

Among High Level Natural Radiation Areas (HLNRAs) all over the world, the northern coastal city of Ramsar has been considered enormously important. Many studies have measured environmental radioactivity in Ramsar, however, no survey has been undertaken to measure concentrations in the diets of residents. This study determined the 226Ra activity concentration in the daily diet of people of Ramsar. The samples were chosen from both normal and high level natural radiation areas and based on the daily consumption patterns of residents. About 150 different samples, which all are local and have the highest consumption, were collected during the four seasons. In these samples, after washing and drying and pretreatment, the radionuclide was determined by α-spectrometry. The mean radioactivity concentration of 226Ra ranged between 5 ± 1 mBq kg-1 wet weight (chino and meat) to 725 ± 480 mBq kg-1 for tea dry leaves. The 226Ra activity concentrations compared with the reference values of UNSCEAR appear to be higher in leafy vegetables, milk and meat product. Of the total daily dietary 226Ra exposure for adults in Ramsar, the largest percentage was from eggs. The residents consuming eggs from household chickens may receive an elevated dose in the diet.