Feline mesenchymal stem cells and supernatant inhibit reactive oxygen species production in cultured feline neutrophils

• Neutrophils play a key role in many pathologic conditions.
• Neutrophil ROS production is inhibited by MSCs.
• Neutrophil ROS production is inhibited by MSC supernatant.
• Neutrophil modulation using either MSCs or supernatant is dose dependent.

Feline bone marrow-derived MSCs (BMMSCs), adipose-derived MSCs (AMSCs) and fibroblasts (FBs) were isolated and cultured. Tri-lineage differentiation assays and flow cytometry were used to characterize MSCs. Neutrophils (NPs) were isolated from whole blood and the NPs production of reactive oxygen reactive oxygen species (ROS) was measured. NPs were cultured alone, with MSC culture supernatant (SN), BMMSCs or AMSCs. NPs incubated with BMMSCs had significantly lower ROS production than NPs incubated with AMSCs (p = 0.0006) or FB (p < 0.0001); NPs ROS production significantly decreased with increasing BMMSC cell number (p = 0.0023) and significantly increased with NPs were incubated with FB compared to BMMSC (p = 0.0003). Both BMMSC SN and AMSC SN had statistically significantly lower ROS production than FB SN when incubated with NPs (both p < 0.0001). ROS production was significantly reduced with increased fractions of SN from BMMSCs (p = 0.0467) and AMSCs (p = 0.0017).