Source-Dependent Phenotypic Differences in Canine Olfactory Ensheathing Cell Cultures from Olfactory Bulb and Mucosa

<b>Background/Aim</b>: Olfactory ensheathing cells (OECs) are widely studied for neural repair, yet OB- and OM-derived primary cultures differ in accessibility and cellular composition. This study aimed to establish donor-matched canine OB- and OM-derived primary cultures using harmonized isolation conditions and to quantify source-dependent differences in culture composition and proliferative activity. <b>Materials and Methods</b>: Olfactory bulbs (OBs) and olfactory mucosa (OM) were collected post-mortem from client-owned dogs (<i>n</i> = 10). Primary cultures were established under identical enzymatic dissociation and culture conditions. Culture composition was quantified by immunocytochemistry using p75^NTR (OEC marker) and fibronectin (fibroblast-associated marker), with an epithelial fraction assessed morphologically in OM. Proliferation was assessed by Ki-67 labeling using the Muse^® Ki-67 kit (<i>n</i> = 5 donors/group). <b>Results</b>: Both tissues yielded viable primary cultures. OB-derived cultures had a higher OEC fraction than OM-derived cultures (60.7 ± 6.4% vs. 39.0 ± 6.2%), whereas OM cultures consistently included an epithelial component (27.0 ± 6.6%). Ki-67 labeling was higher in OB-derived cultures than OM-derived cultures (30.2 ± 6.2% vs. 13.0 ± 2.5%; Welch's <i>t</i>-test <i>p</i> = 0.0018). <b>Conclusions</b>: Canine OB and OM generate source-distinct primary cultures under standardized conditions: OB-derived cultures are OEC-enriched and more proliferative in vitro, while OM-derived cultures are more heterogeneous. These findings inform future optimization of OM-based protocols and motivate functional assays to test regenerative efficacy.