quantitative data on morphometry of rat NMJ

Morphometric ultrastructural analysis of neuromuscular junctions in the rat vastus lateralis muscle after photobiomodulation (PBM, 650 nm, 6 J/cm²).Transmission electron micrographs were analysed using ImageJ (v. 2.14.0). Forty presynaptic terminal profiles (cross-sectional area 1.5–7.4 μm²) from control and PBM-treated muscles were evaluated. Terminals smaller than 1 μm² without mitochondria were excluded.Measured parameters included: presynaptic terminal area and perimeter, maximum and minimum diameters, length of pre- and postsynaptic membranes, synaptic cleft width, number of active zones, and two calculated ratios (PPT/LPOST and LPRE/LPOST).Relative volumes of mitochondria, synaptic vesicles, and axoplasm were quantified using the planimetric method (Delesse principle). Synaptic vesicles were classified into three functional pools: readily releasable (RRP), recycling (RPc), and reserve (RP) based on their distance from the active zone. Mitochondrial density and the ratio of normal to defective mitochondria were also assessed.This dataset contains all raw measurements and calculated indices supporting the manuscript on the effects of PBM on neuromuscular junction ultrastructure in aged rats.