[Embryonic Stem Cell-Derived Mesenchymal Stromal Cell Exosomes Protect Against Radiation-Induced Lymphocyte Injury...

To explore the repair effect and its related mechanism of exosomes derived from embryonic stem cell-induced mesenchymal stromal cells (ESC-MSC) on radiation-induced lymphocyte damage.

A culture system for differentiating embryonic stem cells (ESC) into ESC-MSC was established, with the induced cells identified by flow cytometry and morphological methods. ESC-MSC-derived exosomes (ESC-MSC-Exo) were isolated and purified, followed by identification via electron microscopy, nanoparticle tracking analysis (NTA), and Western blot. Then they were compared with human bone marrow mesenchymal stromal cell-derived exosomes (BM MSC-Exo) to observe their similarities and differences. Lymphocytes from healthy human were isolated and irradiated with 4 Gy ⁶⁰Co γ-rays, then they were co-cultured with ESC-MSC-Exo or BM MSC-Exo for 48 hours. Apoptosis, DNA fragmentation, reactive oxygen species (ROS) production, and mitochondrial membrane potential changes were detected to compare the therapeutic efficacy differences between the two types of exosomes and explore the repair effect and related mechanism of ESC-MSC-Exo on radiation-induced lymphocyte damage.

Flow cytometry and morphological identification confirmed that ESC-MSC expressed mesenchymal stromal cell (MSC) surface markers and exhibited a spindle-shaped morphology. Electron microscopy observation showed ESC-MSC-Exo was cup-shaped or hemispherical with a concave side. Western blot verified the presence of exosomal marker proteins (TSG101, CD63, CD81), and NTA revealed uniform particle size with a peak of 153.6 nm. ESC-MSC-Exo alleviated radiation-induced lymphocyte apoptosis and DNA fragmentation, reduced ROS production, and improved radiation-induced mitochondrial membrane potential depolarization.

ESC-MSC-Exo can mitigate radiation-induced oxidative stress and reduce apoptosis in lymphocytes.