Characterization of Canine Peripheral Blood Stem Cells After Electroacupuncture Stimulation

Abstract Background Although canine mesenchymal stem cells (MSCs) derived from the bone marrow, adipose tissue, and umbilical cord share similar characteristics, the invasive nature of obtaining these tissues through surgical procedures can lead to health complications. Electroacupuncture (EA), a non-invasive alternative method, has been successfully used to stimulate MSC mobilization in horses and rats. However, there is limited information on EA in dogs. Methods MSC mobilization was induced in healthy dogs using EA. Specific acupuncture sites, including GV4 + GV6, SP10 + GB39, and SP10 + LR3 were stimulated in four dogs once a week for 3 weeks. Blood samples were collected for peripheral blood stem cell (PBSC) isolation and culture. Peripheral blood stem cells derived following EA (EA-PBSCs) were characterized and compared with adipose-derived MSCs (AD-MSCs). Results EA-PBSCs adhered to the culture dish surface and exhibited a fibroblast-like morphology similar to that of AD-MSCs. The proliferation rate of EA-PBSCs was substantially lower than that of AD-MSCs ( P < 0.05). Flow cytometry indicated that EA-PBSCs expressed CD34 and CD90 but lacked CD44 and MHC II expression. Moreover, EA-PBSCs showed osteogenic and chondrogenic abilities but not adipogenic differentiation. EA-PBSCs and AD-MSCs exhibited downregulation of immunomodulatory genes, such as interleukin-6 ( IL-6 ), IL10 , prostaglandin E2 ( PGE2 ), hepatocyte growth factor ( HGF ), and indoleamine 2,3-dioxygenase ( IDO ), after priming with interferon-gamma (IFN-γ). Conclusion This study provides promising preliminary insights into the feasibility of isolating EA-PBSCs in dogs. The distinct immunophenotype observed, CD34⁺ with low CD44 and MHC II, suggests that these cells may represent an earlier progenitor or a tissue-specific stem-like population rather than a typical MSC. Further study with refined isolation methods and more donors will be important to confirm these findings and elucidate the nature of these cells. Graphical Abstract