Synergistic Effects of Constraint-Induced Movement Therapy and Mirror Therapy on Neuroplasticity and Functional Recovery in Rats With Hemiplegic Cerebral Palsy

Abstract Importance The mechanisms underlying the combined effects of constraint-induced movement therapy (CIMT) and mirror therapy (MT) on neuroplasticity in hemiplegic cerebral palsy (HCP) remain unclear. Objective This study investigated whether combined CIMT and MT improves functional recovery more than either therapy alone and examined accompanying motor cortical neuroplastic changes. Design HCP rats were randomly assigned to HCP, HCP+CIMT, HCP+MT, and HCP+CIMT+MT groups (n = 13 per group), with a separate control group. Setting The study was conducted at the Experimental Animal Center, Guangzhou Women and Children’s Medical Center, Guangzhou Medical University, Guangzhou, China. Participants The final sample comprised 52 rats with HCP and 13 controls. Interventions Intervention groups received CIMT, MT, or both. Main Outcomes and Measures Rotarod, forelimb suspension, and Y-maze tests assessed motor and cognitive functions. Golgi staining, immunofluorescence, Western blotting, and transmission electron microscopy evaluated dendritic spine density, neuronal survival (neuronal nuclear protein [NeuN]), synaptic proteins (synaptophysin [SY38], postsynaptic density protein 95 [PSD95]), and myelin integrity (myelin basic protein) in the motor cortex. Results The HCP+CIMT+MT group showed greater improvement in rotarod performance than the HCP+CIMT (31.21 s [95% CI = 7.27 to 55.15]) and HCP+MT (26.59 s [95% CI = 1.50 to 51.67]) groups. Longer forelimb suspension times were observed mainly in the MT-containing groups. The HCP+CIMT+MT group showed better Y-maze performance than the HCP and single-therapy groups. Compared with these groups, the combined group showed higher expression of NeuN, SY38, PSD95, and myelin basic protein and improved myelin ultrastructure in the motor cortex. Conclusions Combined CIMT and MT may promote the recovery of motor coordination and balance, support forelimb suspension performance, and improve spatial working memory in rats with HCP. These functional improvements were accompanied by enhanced motor cortical neuroplasticity involving neuronal survival, synaptic remodeling, dendritic spine density, and myelin integrity. Relevance This study provides preclinical evidence on the functional and neuroplastic effects of combined CIMT and MT in HCP.