Mesenchymal Stem Cells Secrete Brain-Derived Neurotrophic Factor and Promote Retinal Ganglion Cell Survival After Traumatic Optic Neuropathy

Objective: The study aimed to investigate whether intravitreal injection of mesenchymal stem cells (MSCs) cultivated in vitro could increase the number of survived retinal ganglion cells (RGCs) after traumatic optic neuropathy and sought to identify potential mechanisms underlying such growth. Methods: The right eye of 24 cats in the MSC transplantation group accepted intravitreal injection of MSCs, and the other 24 cats in the phosphate buffer (PBS) control group received isotonic saline after traumatic optic neuropathy. The RGCs' survival rate in separated retinal and brain-derived neurotrophic factor (BDNF) expression were observed by Dil labeling and Enzyme-Linked Immuno Sorbent Assay (ELISA), respectively, at 3, 7, 14, and 28 days after transplantation. Results: Quantitative analysis showed that RGCs were significantly attenuated at 3, 7, 14, and 28 days after transplantation in both areas of the retina (peripheral, P-7d = 0.0011, P-14d < 0.001, P-28d < 0.001; central, P-3d = 0.0437, P-7d = 0.0067, P-14d < 0.001, P-28d < 0.001). Mean density of RGCs in the MSC transplantation group was significantly higher than that of the PBS control group after 14 days of treatment (P < 0.001). The homogenates BDNF (hBDNF) in the MSC transplantation group was obviously higher than that in the PBS control group at 14 and 28 days (P < 0.05). Conclusions: The MSCs transplanted into the retina of cats can slow down RGC apoptosis and steadily express BDNF. The MSC-mediated neuroprotection after optic nerve injury may be related to BNDF.