Effect of Huangqi On Mesenchymal Stem Cells (MSC) Transplanted Therapy in Spinal Cord Injury: It Promotes the Neural Differentiation of MSC In Vivo.
Authors: Yu Qin , Bai Yueshuang , Lin Jie , Sheng Lixian , Dong Qin , Guo Ying , Xuan Xiaobo 
Published: October 2019

Abstract
Abstract 4476

Introduction
The therapeutic effects of using mesenchymal stem cells (MSCs) for transplantation in the treatment of spinal cord injury have been previously studied. Astragalus propinquus, also known as Huangqi, is a traditional Chinese herb commonly used to strengthen the immune system and protect neuron. However, the possibility of combining the beneficial effects of both MSC transplantation and Huangqi Injecta in treating spinal cord injury has not been addressed.

Methods
A total of 120 male, four-week-old, Wistar rats, were randomly divided into six groups: sham group, model group, phosphate buffered saline (PBS) solution control group (PBS group), Huangqi injection control group (Huangqi group), rMSCs transplantation group (rMSCs group), rMSCs and Huangqi injecta treated group (rMSCs + Huangqi group). There were 10 rats in the sham group and 22 rats in the other groups. In the PBS group, rats were injected 5 μl PBS into the cephalic site of spinal cord injured section three days after the operation; in the Huangqi group, rats were intraperitoneally injected with Huangqi Injecta at a dose of 1.2 ml per 100 g of body weight on day three after the operation; in the rMSCs group, 5 μl of rMSC suspension (2.5–5×105 cells) was injected into the cephalic site of the spinal cord injured part in rats on day three after the operation; in the rMSCs + Huangqi group, rats were injected Huangqi Injecta and 5 μl rMSC suspension (2.5–5×105 cells) following the methods mentioned in the Huangqi group and the rMSCs group. Six animals were randomly picked from each groups on day 7, 14, 21 and 28 to receive Basso-Beattie-Bresnahan (BBB) scale grading for motor function checking of the hind legs. HE staining is adopt for the histopathologic examination, and Dual-marked immunohistochemical analysis is applied for cell locating and differentiation determination.

Results
The average BBB score in the Huangqi group is higher than model group and PBS group, except on day 21. The score in rMSCs group and the rMSCs + Huangqi group is higher than that in the model group, PBS group and the Huangqi group. The rMSCs + Huangqi group has a higher score than the Huangqi group at each time point. Also, except on day 14, the score for the rMSCs + Huangqi group was higher than the rMSCs group, and the difference was significant. HE staining of the spinal cord paraffin sections showed that the degree of degeneration and necrosis in nerve cells was alleviated in the rMSCs and rMSCs + Huangqi groups, compared with the PBS and Huangqi groups. Edema and infiltration of inflammatory cells were obviously reduced, and the proliferation of glial cells and integrated nerve cells was detected in the rMSCs and rMSCs + Huangqi groups. Moreover, the proliferation of glial cells was more active in the rMSCs + Huangqi group than in the rMSCs group. Using immunohistochemical analysis, both in the rMSCs group and the rMSCs + Huangqi group, BrdU marked rMSCs survived in the spinal cord and accumulated in the gray matter more than in the white matter. GFAP + BrdU and BrdU+NF-M positive cells were detected from day 7 after transplantation. The quantity of BrdU + GFAP positive cells in the rMSCs group and rMSCs + Huangqi group is 6.35±1.14 and 8.75±1.16 per visual field relatively, while BrdU + NF-M positive cells in the rMSCs group and rMSCs + Huangqi group is 1.60±0.75 and 3.30±0.98 per visual field relatively. It indicated that the quantity of BrdU + GFAP and BrdU + NF-M positive cells per visual field observed in the spinal cord paraffin section of the rMSCs + Huangqi group, was significantly higher than that in the rMSCs group (P<0.05).

Conclusions
These findings indicated that MSCs transplantation has the capability of nerve restoration and recovery after spinal cord injury, and it could be enhanced by Huangqi Injecta. The strategy of combining Huangqi Injecta and MSCs, aimed to promote transplanted cell differentiation and their tissue repair capability, provided a simple yet effective way of optimizing cell transplantation therapy.

Disclosures:
No relevant conflicts of interest to declare.