Do Nascimento Amorim Maria Do Socorro, Rates Erick Rafael Dias, Isabela Vitoria de Araujo Costa Melo, Silva Diniz Filho Joel Félix, Dos Santos Clenilton Costa, Santos-Oliveira Ralph, Simões Gaspar Renato, Rodrigues Sanches Jonas, Araújo Serra Pinto Bruno, de Andrade Paes Antonio Marcus, Alencar Luciana Magalhães Rebelo
Federal University of Maranhão, Department of Physics, Laboratory of Biophysics and Nanosystems, Campus Bacanga, São Luís, Maranhão 65080-805, Brazil.
Federal University of Maranhão, University School, Campus Bacanga, São Luís, Maranhão 65080-805, Brazil.
ACS Omega. 2024 Sep 19;9(39):40870-40881. doi: 10.1021/acsomega.4c05869. eCollection 2024 Oct 1.
Diabetes Mellitus (DM) is a disease characterized by high blood glucose levels, known as hyperglycemia. Diabetes represents a risk factor for the development of neurodegenerative diseases, such as Alzheimer's Disease (AD), one of the most prevalent neurodegenerative diseases worldwide, which leads to progressive mental, behavioral, and functional decline, affecting many brain structures, especially the hippocampus. Here, we aim to characterize the ultrastructural, nanomechanical, and vibrational changes in hyperglycemic hippocampal tissue using atomic force microscopy (AFM) and Raman spectroscopy. DM was induced in rats by streptozotocin injection (type 1) or dietary intervention (type 2). Cryosections of the hippocampus were prepared and analyzed on an MM8 AFM (Bruker) in Peak Force Quantitative Nanomechanics mode, performing 25 μm scans in 9 regions of 3 samples from each group. Ultrastructural and nanomechanical data such as surface roughness, area, volume, Young's modulus, and adhesion were evaluated. The hippocampal samples were also analyzed on a T64000 Spectrometer (Horiba), using a laser λ = 632.8 nm, and for each sample, four spectra were obtained in different regions. AFM analyses show changes on the ultrastructural scale since diabetic animals had hippocampal tissue with greater roughness and volume. Meanwhile, diabetic tissues had decreased adhesion and Young's modulus compared to control tissues. These were corroboratedby Raman data that shows changes in the molecular composition of diabetic tissues. The individual spectra show that the most significant changes are in the amide, cholesterol, and lipid bands. Overall, the data presented here show that hyperglycemia induces biophysical alterations in the hippocampal tissue of diabetic rats, providing novel biophysical and vibrational cues on the relationship between hyperglycemia and dementia.
糖尿病（DM）是一种以血糖水平升高即高血糖为特征的疾病。糖尿病是神经退行性疾病发展的一个风险因素，如阿尔茨海默病（AD），它是全球最常见的神经退行性疾病之一，会导致渐进性的精神、行为和功能衰退，影响许多脑结构，尤其是海马体。在此，我们旨在使用原子力显微镜（AFM）和拉曼光谱来表征高血糖海马组织的超微结构、纳米力学和振动变化。通过链脲佐菌素注射（1型）或饮食干预（2型）在大鼠中诱导糖尿病。制备海马体的冷冻切片，并在MM8 AFM（布鲁克公司）上以峰值力定量纳米力学模式进行分析，在每组3个样本的9个区域进行25μm的扫描。评估表面粗糙度、面积、体积、杨氏模量和粘附力等超微结构和纳米力学数据。还使用波长λ = 632.8nm的激光在T64000光谱仪（堀场公司）上对海马体样本进行分析，每个样本在不同区域获得四个光谱。AFM分析显示了超微结构尺度上的变化，因为糖尿病动物的海马组织具有更大的粗糙度和体积。同时，与对照组织相比，糖尿病组织的粘附力和杨氏模量降低。拉曼数据证实了这些结果，该数据显示了糖尿病组织分子组成的变化。单个光谱表明，最显著的变化发生在酰胺、胆固醇和脂质带。总体而言，此处呈现的数据表明高血糖会诱导糖尿病大鼠海马组织发生生物物理改变，为高血糖与痴呆之间的关系提供了新的生物物理和振动线索。
