# Repeated Intrathecal Stem Cells Optimize Neuroplasticity and Motor Function in Moderate‐to‐Severe Cerebral Palsy of Rats

## TL;DR

Repeated injections of stem cells improved motor function and brain repair in rats with severe cerebral palsy more than a single injection.

## Contribution

This study shows repeated stem cell injections are more effective than single injections in a severe cerebral palsy rat model.

## Key findings

- Repeated hUC-MSC injections improved motor performance and brain structure more than single injections.
- Stem cells reduced inflammation and supported myelin repair in the brain.
- Lentivirally transfected hUC-MSCs survived in the damaged brain area for at least 3 days.

## Abstract

Human umbilical cord‐derived mesenchymal stem cells (hUC‐MSCs) ameliorate motor deficits in cerebral palsy (CP), but the effect of injection frequency remains unclear. Moreover, most studies have focused on mild CP models (unilateral carotid artery occlusion [UCAO] model). This study explored the effect and mechanism of hUC‐MSCs in a rat model of moderate‐to‐severe CP (bilateral carotid artery occlusion [BCAO] model). On postnatal Day 4 (P4), Wistar rat pups underwent BCAO induction. Subsequently, they received either a single intrathecal injection of hUC‐MSCs on P21 or repeated injections on P21, P28, P35, and P42. Motor performance was assessed using the rotarod and front‐limb suspension tests, while neuronal regeneration and inflammation were evaluated via biomarkers including neuronal nuclear antigen (NeuN), ionized calcium‐binding adapter molecule‐1 (Iba‐1), glial fibrillary acidic protein (GFAP), myelin basic protein (MBP), and brain‐derived neurotrophic factor (BDNF). P18 model screening confirmed that the BCAO model resulted in more severe brain damage and motor impairment than the UCAO model. After injection of lentivirally transfected hUC‐MSCs, it was found that hUC‐MSCs could nest in the damaged area and survive for at least 3 days. Administration of hUC‐MSCs following BCAO modeling led to notable improvements in both behavioral performance and histological outcomes. Furthermore, repeated injections offered greater therapeutic benefits compared to single injection. It indicated that the efficacy of repeated injections of hUC‐MSCs in the treatment of moderate‐to‐severe CP was superior to that of single injection. Its mechanism was related to the improvement of damaged myelin structure, reduced immunoinflammatory responses, and increased neurotrophic support.