Repairing effect of Schwann cells combined with mesenchymal stem cells on optic nerve injury in rats.

Abstract

To investigate the effect and the underlying mechanisms of combined transplantation of Schwann cells (Scs) and Mesenchymal stem cells (MSCs) on optic nerve injury in rats. A total of 160 normal healthy adult rats were randomly divided into 4 groups: optic nerve injury group, optic nerve injury + Sc transplantation group, optic nerve injury + MSC transplantation group and optic nerve injury + Sc + MSC transplantation group. The optic nerve in the left eye of each rat was damaged via clamping to establish a model of optic nerve injury, and the right eye was used as self-control. Scs + MSCs, Scs alone, MSCs alone and normal saline were injected into the vitreous space, respectively. After the treatment, the optic nerve tissues were collected and subjected to hematoxylin-eosin (HE) staining. Next, the morphologic and pathological changes of rats in each group were observed. Retrograde labeling was utilized to count the number of retinal ganglion cells (RGCs) in the optic nerve tissues. The apoptosis of RGCs was detected using flow cytometry. Western blot was carried out to measure the protein expression level of B-cell lymphoma 2 (Bcl-2) and Bcl-2-associated X protein (Bax). The expression and distribution of brain-derived neurotrophic factor (BDNF) and growth associated protein-43 (GAP-43) in the optic nerve of rats in each group were detected by immunohistochemistry. Transplantation of Scs and MSCs could maintain the morphological structures of the retina and optic nerve of rats, increase the amount of RGCs in optic nerve tissues, reduce the apoptosis of RGCs, promote the expression of the Bcl-2 protein and decrease the expression of Bax protein. In addition, our joint transplantation strategy also showed an important role in repairing optic nerve injury by clearly promoting the secretion and expression of BDNF and GAP-43, which indicated a better curative effect than that of separate application of Scs or MSCs. Therapy with combined use of Scs and MSCs has a significant therapeutic effect in repairing optic nerve injury.