EVALUATING THE AMELIORATIVE EFFECT OF MSCS AND EXOSOMES ON MWCNTS LUNG TOXICITY USING HISTOPATHOLOGY AND MORPHOMETRY IN RATS

The growing use of multi-walled carbon nanotubes (MWCNTs) in industry and medicine has raised concerns about their potential toxicity to human and animal health, particularly their ability to cause oxidative stress, inflammation, and fibrosis. Mesenchymal stem cells (MSCs) and their exosomes have emerged as promising therapeutic agents due to their effective immunomodulatory, anti-inflammatory, and antioxidant properties. Herein, we investigate the effects of MSCs and MSC-derived exosomes against MWCNTs-induced pulmonary toxicity in albino rats. Thirty-two male rats (4 weeks old) were divided into four groups: (1) a control group receiving normal saline, (2) an MWCNTs-exposed group administered MWCNTs (1 mg/kg BW, intraperitoneally (IP), twice at the first and third weeks), (3) an MWCNTs + MSCs + exosomes-treated group receiving MWCNTs (1 mg/kg BW, IP) followed by MSCs (2.5 × 10⁶ cells/kg BW, IP) and exosomes (100 µg MSC-EV protein/kg BW, IP) weekly for three weeks, and (4) an MSCs + exosomes-only group receiving the same MSC and exosome doses without MWCNT exposure. MWCNTs exposure resulted in a significant increase in bronchiolar epithelial thickness, goblet cell hyperplasia, elevated fibrosis levels (Masson's trichrome staining), and increased oxidative stress markers, including malondialdehyde (MDA). These effects were mitigated by MSCs and exosomes through reducing epithelial thickening and goblet cell hyperplasia, decreasing fibrosis, and restoring antioxidant markers such as glutathione (GSH). Histopathological analysis confirmed lung regeneration by decreasing inflammation, degeneration, and fibrosis. These findings highlight the therapeutic potential of MSC-based therapy and the value of digital pathology tools like ImageJ in nanotoxicology research. Keywords: Image J, MWCNTs, MSC-derived Exosomes, Morphometric Analysis, Pulmonary Toxicity