The Effect of Low Dose Radiation on Alzheimer's Disease-Induced TG Mice

Abstract

Alzheimer's disease is the most common form of dementia, with 70% of dementia. The number of demented patients aged 5 years and older is estimated to be 648,223 (prevalence 9.8%) in 2015, but doubling every seven years to exceed 2 million (12.3%) in 2041. Alzheimer's findings are as follows: Significant decline in memory and cognitive function and post-necropsy findings suggest that senile plaques, which are extrinsic to Aβ in the brain tissue, and nerve fiber masses, mainly composed of hyperphosphorylated tau proteins, Neurofibrillary tangles are present. Therefore, we investigated the effects of radiation on Alzheimer's disease by administering low doses of radiation to Alzheimer's disease-induced TG mice. We had 7-month-old APP / PS / Tau triple TG mice that were exposed to whole-brain irradiation of either 2 Gy ioninzing-radiation at 5 times with total 10Gy. Changes in cognitive function were confirmed by cognitive testing before and after radiotherapy. The cognitive test used the water maze test method. Through the sacrifice, we acquired the brain of the mouse and confirmed the changes senile plaque, monomer Aβ, oligomer Aβ through immunofluorescent staining. In the case of Alzheimer's disease mice, we compared the results of cognitive testing with water maze test after radiotherapy compared to before radiotherapy. Control group C57BL / 6 mice took a time approximately 28s. However, Alzheimer's disease mice took about 165s before the radiation treatment, and it took 54s after the fourth week of radiation therapy, and it was gradually accelerated to 32s after 8 weeks. This time is similar duration for control mice. After 8 weeks of stabilization period after radiation therapy, mouse brain was acquired and immunofluorescent staining was performed. Senile plaque and monomer Aβ staining showed that the plaque was remarkably reduced and the monomer Aβ was also reduced after radiation therapy in mice induced with Alzheimer 's disease too. Especially, oligomer Aβ was found in the cortex area. Activated microglia were also accumulated in the vicinity of the cortex, but oligomer Aβ and microgia were also decreased after radiation treatment. Oligomer Aβ was identified in the hippocampus. However, oligomer Aβ was significantly reduced after radiation therapy. his study confirmed the improvement of cognitive ability as a result of low doses of radiation therapy in mice with Alzheimer's disease. To confirm immunologically, a variety of Aβ, which is known to be one of the causes of Alzheimer's disease, was stained and confirmed that Aβ was reduced. Therefore, low dose radiation therapy in Alzheimer 's disease mice seems to be effective. This study is currently underway and will be evaluated with a larger number of individuals. And, studies of mechanisms are required to understand how low dose radiation affects Alzheimer's disease.