Human umbilical cord mesenchymal stem cell-derived exosomes combined with mouse nerve growth factor can more effectively ameliorate the motor disorder and brain pathological injury in mice with cerebral palsy

Background: Cerebral palsy (CP) is a neurodevelopmental disorder and motor disorder syndrome. It has been confirmed that mesenchymal stem cells (MSCs) and mouse nerve growth factor (mNGF) can repair brain tissue damage and nerve injury; however, exosomes derived from healthy cells may have a comparable therapeutic potential as the cells themselves.

Objectives: The purpose of this study was to explore the improvement effect of human umbilical cord mesenchymal stem cell (hUC-MSCs)-derived exosomes on a CP model and determine whether there is a synergistic effect when combined with mNGF.

Material and methods: Exosomes were isolated from hUC-MSCs and examined using transmission electron microscopy (TEM), particle size and western blot (WB). A total of 38 BALB/c mice (male, postnatal day 6 (PND6)) were randomly divided into 5 groups: sham group, CP group, CP-exo group, CP-mNGF group, and CP-exo-mNGF group. Hypoxic induction after unilateral common carotid artery ligation combined with lipopolysaccharide (LPS) infection was used to construct the CP model. Pathological damage to neuron tissue and synaptic structures in the hippocampus was confirmed using light microscopy after hematoxylin-eosin (H&E) staining and TEM, respectively. Survival of neurons was evaluated using Nissl staining. Western blot was applied to monitor PSD-95 and synaptophysin (SYN) protein levels.

Results: This study indicated that exosomes released by hUC-MSCs ameliorated brain damage and synaptic structure destruction in CP mice induced by hypoxic ischemia and LPS infection. When combined with mNGF, there was more effective improvement. In the CP group, neuronal function was severely impaired; however, hUC-MSCs-derived exosomes and mNGF improved it. PSD-95 and SYN proteins were presynaptic and postsynaptic proteins, respectively. Interestingly, the PSD-95 and SYN protein levels were significantly lower in the CP mice, but with the addition of hUC-MSCs-exosomes or mNGF, they increased significantly, especially in the CP-exo-mNGF group.

Conclusions: The nerve function injury in CP can be improved the most when hUC-MSCs-derived exosomes are combined with mNGF through intraperitoneal (ip.) administration.