Administration of adipose tissue-derived mesenchymal stem cells and bone marrow-derived mesenchymal stem cells in anosmic mice.

Background/aim: Anosmia, a serious condition that affects the sense of smell, has no universally agreed-upon treatment. Adult stem cells are considered a potential option for treating anosmia. This study aims to evaluate the efficacy of mesenchymal stem cells derived from different tissues in an anosmic mouse model induced by 3-methylindole (3-MI).

Materials and methods: In our study, 36 mice with 3-MI-induced anosmia were divided into subgroups. Anosmia was confirmed by performing a food-finding test (FFT) in each group. Intranasal phosphate-buffered saline was administered to the first group, adipose tissue-derived mesenchymal stem cells (ADSCs) to the second group, and bone marrow-derived mesenchymal stem cells (BMSCs) to the third group. Stem cells were obtained from green fluorescent protein (GFP)-transgenic mice. Olfactory function was evaluated weekly using the FFTs. Mice were sacrificed at the second and fourth weeks following 3-MI injection and examined histopathologically.

Results: Compared to the control group, stem cell-transplanted groups demonstrated significantly improved food-finding times measured at week 2 and week 4 FFTs following the 3-MI injection (respectively; p = 0.001, p = 0.008). Additionally, increased olfactory marker protein expression and olfactory epithelial thickness, along with reduced epithelial damage, were observed in the stem cell-transplanted groups compared to the control group (p < 0.05). Histologically, BMSCs showed greater efficacy than ADSCs in promoting olfactory regeneration. Furthermore, GFP+ cells were detected in the olfactory epithelium and olfactory bulbs of the stem cell-transplanted groups.

Conclusion: It was observed that intranasally transplanted stem cells could reach the damaged olfactory region and enhance olfactory regeneration and functional recovery. Both ADSCs and BMSCs were effective in treatment and appear to be promising therapeutic modalities.