In addition, the expression of mitochondrial fusion proteins (i.e., Mfn1 and OPA1) was significantly decreased in the cortex and hippocampus of AD animals (Cortex-Mfn1: P = 0.005; Hippocampus-Mfn1: P = 0.0014; Cortex-OPA1: P < 0.001; Hippocampus-OPA1: P = 0.00264), and significantly preserved by PBM treatment (Cortex-Mfn1: P = 0.0038; Hippocampus-Mfn1: P = 0.0029; Cortex-OPA1: P = 0.0026; Hippocampus-OPA1: P = 0.0015). This evidence concerns the gene MFN1 and Alzheimer disease.