In vivo evaluation of therapeutic and tissue regenerative potential of mesenchymal stem cells chronic mastitis in mice

In the intricate world of dairy health, where mastitis reigns as a costly nemesis, the traditional reliance on antibiotics faces its own set of hurdles. Efficacy concerns, the intricate web of causes, rising antimicrobial resistance, and the inability to restore the damaged mammary tissue to its former glory have spurred a quest for innovative solutions. Mesenchymal Stem Cell (MSC) therapy is a rising star in the realm of degenerative disease management. With the growing clinical spotlight, MSCs hold the potential to fill the void in treating conditions where effective solutions have remained elusive. Yet, within this landscape, the therapeutic applications of MSCs in mastitis remain relatively uncharted territory. This study embarks on exploration, seeking to unveil the regenerative potential of mesenchymal stem cells in the context of mastitis induced in mice, offering a promising path towards transformative breakthroughs in dairy animal health. In the present study, murine bone marrow- MSCs were isolated, cultured, expanded, and characterized for MSCs-specific markers. The 10-15 days post parturient lactating mice were used for the study (group A: healthy control with phosphate-buffered saline (PBS) inoculation in mammary gland on day 0 and day 20; group B: chronic mastitic mammary gland + PBS treatment; group C: chronic mastitic mammary gland +stem cell treatment). Upon stem cell treatment, fibrotic mammary glands (group C) showed reduced inflammation, degeneration, and necrosis with few inflammatory cells’ infiltration, and deposition of less amount of collagen fibers compared to the control. The normal architecture of the glandular epithelium, adipocytes, and other associated structures was observed in some areas of the sections, both at gross and histological levels, at 15- and 30-days post stem cell treatment. Results were further validated at the molecular level using RT-qPCR, which showed that murine MSCs treatment significantly upregulated the mRNA expression of antiapoptotic (Bcl-2), anti-inflammatory (IL-10), and angiogenic genes (VEGF-A) while downregulated the proinflammatory (IL-6), profibrotic (TGFβ-1) and apoptotic genes (Caspase-3) in the fibrotic mammary gland.