In vivo effects of adipose-derived stem cells in inducing neuronal regeneration in Sprague-Dawley rats undergoing nerve defect bridged with polycaprolactone nanotubes

Abstract

There have been many attempts for regeneration of peripheral nerve injury. In this study, we examined the in vivo effects of non-differentiated and neuronal differentiated adipose-derived stem cells (ADSCs) in inducing the neuronal regeneration in the Sprague-Dawley (SD) rats undergoing nerve defect bridged with the PCL nanotubes. Then, we performed immunohistochemical and histopathologic examinations, as well as the electromyography, in three groups: the control group (14 sciatic nerves transplanted with the PCL nanotube scaffold), the experimental group I (14 sciatic nerves with the non-differentiated ADSCs at a density of 7×10(5) cells/0.1 mL) and the experimental group II (14 sciatic nerves with the neuronal differentiated ADSCs at 7×10(5) cells/0.1 mL). Six weeks postoperatively, the degree of the neuronal induction and that of immunoreactivity to nestin, MAP-2 and GFAP was significantly higher in the experimental group I and II as compared with the control group. In addition, the nerve conduction velocity (NCV) was significantly higher in the experimental group I and II as compared with the control group (P=0.021 and P=0.020, respectively). On the other hand, there was no significant difference in the NCV between the two experimental groups (P>0.05). Thus, our results will contribute to treating patients with peripheral nerve defects using PCL nanotubes with ADSCs.

Keywords: Adipose Tissue; Matrix Attachment Regions; Nanotubes; Peripheral Nerves; Polycaprolactone; Regeneration; Stem Cells.

Fig. 1

MWNT/PCL nano-composite tube. (A) Grossly, it has a white, flexible, hollow tube-like structure. (B) On SEM, it has a diameter of approximately 2.7 mm and a lumen diameter of approximately 1.2 mm (low-power fields). (C) On SEM, it has a mean diameter of 2±0.5 µm (high-power fields).

Fig. 2

Flow cytometry of the cultured ADSCs.

Fig. 3

The in vivo effects of ADSCs in inducing the neuronal differentiation. (A) Baseline, (B) At 1 hr, (C) At 3 hr, (D) At 1 day, and (E) At three days.

Fig. 4

Immunohistochemical findings. (Left) control group and (Right) neuronal induction. (A) β-tubulin, (B) NCAM, (C) S-100, (D) NeuN and (E) NSE.

Fig. 5

Surgical exposure of the sciatic nerve. (A) The exposure of the sciatic nerve and (B) The implantation of the nanofibers.

Fig. 6

Histologic and immunohistochemical findings. On both histopathologic and immunohistochemical examinations, the degree of nerve regeneration is higher in the experimental groups. H&E, Toluidine blue-O (blue), Nestine (green), MAP-2 (red), GFAP (green).

Fig. 7

Electromyography. Experimental group I (B) and experimental group II (C) show strong evoked action potential (A: control group).

Fig. 8

Nerve conduction velocity. Nerve conduction velocity of experimental group I (B) and II (C) was improved more than that of control group (A) on electromyography. ^*Statiscally significant difference, P<0.05.