The Role of Human Neural Stem Cell Secretomes on the Repair of Spinal Cord Injury Post-laminectomy in Rattus norvegicus Through the Analysis of Basso-Beattie-Bresnahan Score Locomotors, Interleukin-10, Matrix Metalloproteinase 9, and Transforming Growth Factor-β

Abstract

Study design: Experimental animal study.

Purpose: This study aims to investigate the effects of treatment with human neural stem cell (HNSC) secretomes on subacute spinal cord injury (SCI) post-laminectomy by analyzing interleukin-10 (IL-10), matrix metalloproteinase 9 (MMP9), transforming growth factor-β (TGF-β), and Basso-Beattie-Bresnahan (BBB) score locomotors as expressions of neurological recovery.

Overview of literature: In the United States, SCI has a recovery rate of 0.08%, tetraplegia 58.7%, and paraplegia 40.6%. Therapeutic approaches to SCI have focused on modulating the secondary cascade to prevent neurological deterioration and glial scar formation. Increasing evidence has shown that the success of cell-based SCI therapy is attributed to the secretomes rather than the cells themselves, but the effect of treatment with HNSC secretomes in SCI is unclear.

Methods: This experimental study investigated 15 Rattus norvegicus rats that were divided into three groups: (1) normal, (2) SCI+nonsecretome, and (3) SCI+secretome (30 μL, intrathecal Th10). Model subacute SCI post-laminectomy was performed in 60 seconds using an aneurysm Yasargil clip with a closing forceps weighing 65 g (150 kdyn). At 35 days post-injury, the specimens were collected, and the immunohistochemicals of IL-10, MMP9, and TGF-β were analyzed. Motor recovery was evaluated based on the BBB scores.

Results: The SCI post-laminectomy of rats treated with HNSC secretomes showed improvements in their locomotor recovery based on the BBB scores (p =0.000, mean=18.4) and decreased MMP9 (p =0.015) but had increased the levels of IL-10 (p =0.045) and TGF-β (p =0.01).

Conclusions: These results indicate that the factors associated with the HNSC secretomes can mitigate their pathophysiological processes of secondary damage after SCI and improve the locomotor functional outcomes in rats.

Keywords: Interleukin-10; Locomotors; Matrix metalloproteinase 9; Secretome; Transforming growth factor-β.

Fig. 1

(A) Contusion compression of the spinal cord at the Th10 level with aneurysm Yasargil clip. (B) 5 cm speciment spinal cord injury was separated from the vertebral column and marked at the cranial end.

Fig. 2

(A) Evaluation Basso–Beattie–Bresnahan (BBB) scores in rat secretomes day group. (B) Evaluation BBB scores in rat non-secretomes group.

Fig. 3

Graph of Basso–Beattie–Bresnahan (BBB) scores locomotors recovery (mean). SCI, spinal cord injury.

Fig. 4

We observed immunohistochemical IL-10 average value of 10 field of views, every field of view have 625 μ² with 400× magnification. The mean number of IL-10 expressed cells in the (A) normal group was (mean=0.800), (B) spinal cord injury (SCI)+secretome group (mean=4.000), and (C) SCI+non-secretome group (mean=1.800). Microglia are small round cells, solid nuclei and give a positive reaction with anti IL-10 indicated by brown color. While macrophage cells are large, vesicular nucleus, and sometimes elongated resembling fibroblasts (macrophages like fibroblast) and give a positive reaction with anti IL-10 indicated by brown.

Fig. 5

We observed immunohistochemical transforming growth factor-β (TGF-β) average value of 10 field of views, every field of view have 625 μ² with 400× magnification. The mean number of TGF-β expressed cells in the (A) normal group was (mean=0.800), (B) spinal cord injury (SCI)+secretome group (mean=3.800), and (C) SCI+non-secretome group (mean=2.000). Microglia are small round cells, solid nuclei and give a positive reaction with anti TGF-β indicated by brown color. While macrophage cells are large, vesicular nucleus, and sometimes elongated resembling fibroblasts (macrophages like fibroblast) and give a positive reaction with anti TGF-β indicated by brown.