Biodistribution of poly clustered superparamagnetic iron oxide nanoparticle labeled mesenchymal stem cells in aminoglycoside induced ototoxic mouse model

Abstract

Recently, application of stem cell therapy in regenerative medicine has become an active field of study. Mesenchymal stem cells (MSCs) are known to have a strong ability for homing. MSCs labeled with superparamagnetic iron oxide nanoparticles (SPIONs) exhibit enhanced homing due to magnetic attraction. We have designed a SPION that has a cluster core of iron oxide-based nanoparticles coated with PLGA-Cy5.5. We optimized the nanoparticles for internalization to enable the transport of PCS nanoparticles through endocytosis into MSCs. The migration of magnetized MSCs with SPION by static magnets was seen in vitro. The auditory hair cells do not regenerate once damaged, ototoxic mouse model was generated by administration of kanamycin and furosemide. SPION labeled MSC's were administered through different injection routes in the ototoxic animal model. As result, the intratympanic administration group with magnet had the highest number of cells in the brain followed by the liver, cochlea, and kidney as compared to those in the control groups. The synthesized PCS (poly clustered superparamagnetic iron oxide) nanoparticles, together with MSCs, by magnetic attraction, could synergistically enhance stem cell delivery. The poly clustered superparamagnetic iron oxide nanoparticle labeled in the mesenchymal stem cells have increased the efficacy of homing of the MSC's to the target area by synergetic effect of magnetic attraction and chemotaxis (SDF-1/CXCR4 axis). This technique allows delivery of the stem cells to the areas with limited vasculatures. The nanoparticle in the biomedicine allows drug delivery, thus, the combination of nanomedicince together with the regenerative medicine will provide highly effective therapy.

Keywords: Homing; Mesenchymal stem cell; Ototoxicity; SPION.

Fig. 1

Characterization of PCS nanoparticles. a Schematic illustration of PCS nanoparticle preparation. b Hydrodynamic diameter of PCS. c Zeta-potential of PCS. d SEM image of PCS. e TEM image of PCS. f Fe ion measurement in PCS nanoparticle solution. g FT-IR analysis of PLGA and PLGA-Cy5.5

Fig. 2

MSCs internalization by PCS. A Cytotoxicity test of PCS nanoparticle in concentration and time dependent manner. B Mesenchymal stem cell labeled with 40 ug/mL YRB for 24 h. a DAPI, b GFP, c Cy-5.5 in PCS nanoparticle, d merge (scale bar: 20 μm). C Differentiation of MSCs into adipocyte and osteocyte. a control (without adipogenic factors) b adipogenic differentiation without PCS c adipogenic differentiation with PCS (blue: DAPI, green: mFABP4). d control (without osteogenic factors) e osteogenic differentiation without PCS f osteogenic differentiation with PCS (blue: DAPI, green: mOsteopontin) (scale bar: 50 μm)

Fig. 3

MSCs time-dependent migration to the magnet in vitro (3 mm) 24 h and 48 h. a Fluorescent microscopic images of magnetic attraction test in vitro at 24 h (up) and 48 h (down). b Quantification of magnetic attraction test at 24 h (left) and 48 h (right) (*p < 0.05, n = 3)

Fig. 4

Transwell migration assay of MSC; chemoattraction and magnetic attraction; a, d Control, b e MSC labeled with PCS nanoparticle and SDF-1 in lower chamber c, f MSC labeled with PCS nanoparticle and SDF-1 and magnet exposure for 24 h

Fig. 5

ABR (Auditory brainstem response) of ototoxic mouse model and FOBI analysis. a ABR test compared pre-injection to post-injection of ototoxic drug. b biodistribution of MSC after administration. c Mean fluorescence intensity analysis among experimental groups

Fig. 6

Biodistribution of MSC-GFP in vivo ototoxic mouse model; reverse transcriptase PCR results quantifying GFP levels in the different tissue samples

Fig. 7

Fluorescent microscopic images of biodistribution of MSC-GFP In vivo ototoxic mouse model. A Average number of green fluorescence expressing cells observed in the samples according to study group. B Fluorescent images of GFP expressing MSC; a–c Liver, d–f kidney, g–i brain, j–l cochlea