Comparison of human adipose-derived stem cells and chondroitinase ABC transplantation on locomotor recovery in the contusion model of spinal cord injury in rats

Abstract

Objectives: Spinal cord injury (SCI) is one of the most serious clinical diseases and its treatment has been a subject of interest to researchers. There are two important therapeutic strategies in the treatment of SCI: replacing lost tissue cells through cells implantation and scar elimination. Therefore, in this study we used human adipose-derived stem cells (hADSCs) implantation and injection of Chondroitinase ABC. Aim of present study was to answer to this question: which one is more efficient for Improvement of locomotor recovery after SCI in rat? Transplantation of hADSCs or injection of ChABC.

Materials and methods: The spinal cord of rats was injured by contusion using a weight-drop at the level of T8-9, the hADSCs and Chondroitinase ABC were infused in to the spinal cord tissue after injury. BBB test was performed and recorded for each animal weekly for 8 weeks. After the 8(th) weeks, Serial cross-sections were stained with cresyl violet and examined under a light microscope and area of cavity in the spinal cord was measured.

Results: At 8(th) weeks after injection, hADSCs and ChABC significantly promote locomotor function (P<0.01) and spinal cords of hADSCs and ChABC group had cavities much smaller than those of the control group (P<0.001).

Conclusion: Results of the present study shows dealing with inappropriate neuro-inhibitory environment and glial scar by ChABC have equal role compare to cell therapy (with hADSCs) for improving motor function after SCI and this result in adoption of proper therapeutic strategies for SCI intervention is important.

Keywords: BBB; Chondroitinase ABC; Contusion; Spinal Cord Injury; hADSCs.

Figure 1.

Characterization of isolated human adipose-derived stem cells. (A) Inverted microscopy of the spindle-shape and fibroblast- like morphology of hADSCs in the fourth passage. (B) Flowcytometry analysis of hADSCs: the results showed that hADSCs expressed, CD44, CD73 and CD90 but did not express CD31 and CD45. The experiments were repeated three times

Figure 2.

hADSCs express GFP in proliferation medium 10 days after transduction; left and right : cells grown in monolayer; right is GFP positive cells

Figure 3.

The graph shows mean BBB after SCI until 9 weeks. Significant difference between Ch ABC and Control groups started At once week after injection (14 days after surgery) (*P<0.001). Significant difference between hADSCs and Control groups started At third week after injection (28days after surgery) (**P<0.01).At eighth week after injection (63 days after surgery) there was significant difference between Ch ABC, hADSCs and Control groups(▼P<0.01)

Figure 4.

10 µm thick cross sections of spinal cord segments T8-9 of sham operative group (A), control group (B), hADSCs group (C) and ChABC group (D) at 8 weeks after surgery. Spinal cord tissue was stained with Cresyl violet. A large cavity was shown from non treated animals. The cavity formation was reduced in treated animals

Figure 5.

(A) Low magnification of the GFP-positive hADSCs (green) located within the lesion 8 weeks after transplantation. (B) hADSCs in A are shown at higher magnification. Stars indicates the cystic cavity and arrow indicates GFP-positive hADSCs that migrating into the host tissue around the cystic cavity

Figure 6.

These graph show the difference in size of cavities between the hADSCs, ChABC-injected and control groups at 8 weeks after injection. The values of the cavity size were significantly different between the hADSCs, ChABC-injected and control groups (*P<0.001)