Constraint-induced movement therapy combined with mesenchymal stem cell transplantation promotes myelination and functional recovery by inhibiting PRKCD/MEK/ERK pathway in hemiplegic cerebral palsy rats.

The core problem of hemiplegic cerebral palsy (HCP) is upper limb motor deficits with high rates of disability. Given the shared goals of stem cell therapy and rehabilitation, this study investigated the synergistic effects of constraint-induced movement therapy (CIMT) and human umbilical cord-derived mesenchymal stem cells (hUC-MSCs) transplantation in promoting motor recovery and elucidates the underlying mechanisms in HCP. The rats were allocated to a control group and HCP groups receiving different interventions (CIMT, hUC-MSCs or combination treatment), namely, the Control, HCP, HCP + CIMT, HCP + MSC, and HCP + CIMT + MSC groups. Motor function was evaluated using rotarod duration, grip strength, and forelimb suspension time. Golgi-Cox staining, transmission electron microscopy, immunofluorescence staining, Western blotting, quantitative real-time PCR and label-free proteomic quantification technology were used to measure dendritic/axonal area, myelin integrity, oligodendrocyte (OL)/oligodendrocyte precursor cell (OPC)-associated proteins and PRKCD/MEK/ERK expression in the motor cortex. Rats in the HCP + CIMT + MSC group exhibited improved motor function, increased dendritic spines and branches, enhanced myelin integrity, higher numbers of Olig2+OL, CNPase+OL and MBP+OL, and reduced NG2+OPC counts in the motor cortex compared to the HCP group (p < 0.05). Additionally, motor performance in the HCP + CIMT + MSC group was significantly superior to than those in the HCP + CIMT and HCP + MSC groups (p < 0.05). Moreover, proteomic analysis identified that PRKCD, a key mediator of the synergistic effect, was expressed in OPC and implicated in their physiological processes. Rats in the HCP + CIMT + MSC group also showed reduced PRKCD protein and mRNA expression, fewer PRKCD+/NG2+ cells, higher CNPase+/PRKCD+ area ratio and lower levels of MEK1/2 and ERK1/2 phosphorylation relative to the HCP group (p < 0.05). CIMT combined with hUC-MSCs transplantation synergistically promoted OPC differentiation into immature OL, induced myelination, and restored motor function in HCP rats, potentially by inhibiting the PRKCD/MEK/ERK pathway. This combined approach expands therapeutic options for HCP and identifies a promising target for future interventions.