ObjectiveThis paper aims to analyze the damage degree of muscle tone in rats with spasticity of cerebral apoplexy （SCA） and the expression of Nestin and β-catenin in the M1 region of the cerebral cortex， thereby investigating the action mechanism of different doses of Shaoyao Gancaotang on rats with SCA. MethodsThe rats were randomly divided into a blank group， a model group， a positive control group （baclofen， 5.25 mg·kg^-1）， and low， medium， and high-dose groups of Shaoyao Gancaotang （2.1， 4.2， 8.4 g·kg^-1）， with nine rats in each group. A rat model with SCA was established by using a modified phrenic nerve block combined with intraventricular injection of anhydrous ethanol. Following behavioral scoring to confirm model validity， drug interventions were conducted. Neurological deficits and muscle tone were evaluated by behavioral assessments. The open field test was used to measure locomotor distance. Transmission electron microscopy was employed to examine the synaptic structures. Skeletal muscle adenosine triphosphate （ATP）ase staining was used to analyze myofibrillar changes. Hematoxylin and eosin （HE） staining was used to observe the histomorphological changes. Immunohistochemistry， Real-time polymerase chain reaction （Real-time PCR）， and Western blot were employed to detect mRNA levels and protein expressions of Nestin and β-catenin in the M1 region of the cerebral cortex. ResultsCompared with the blank group， rats in the model group exhibited significantly increased neurological deficit scores （P<0.01）， markedly elevated muscle tone scores （P<0.01）， substantially reduced locomotor distance （P<0.01）， prominent structural swelling and blurring， severe destruction of cerebral cortical cells， a significant increase in the proportion of skeletal muscle ATPase type Ⅰ fibers （P<0.01）， a significant decrease in mRNA levels and protein expression of Nestin （P<0.01）， and a significant increase in mRNA levels and protein expression of β-catenin （P<0.01）. Compared with the model group， the Shaoyao Gancaotang group exhibited reduced neurological deficit scores and muscle tone scores in rats with SCA （P<0.01） and increased locomotor distance （P<0.01）. Transmission electron microscopy revealed clearer and more intact synaptic structures in the rats from the Shaoyao Gancaotang group， with increased vesicle numbers and improved morphology. HE staining revealed intact neuronal cell structures with regular arrangement and reduced vacuolated cells in the rats from Shaoyao Gancaotang. ATPase staining result indicated a decreased proportion of type Ⅰ muscle fibers in the rats from the Shaoyao Gancaotang group （P<0.01）. Real-time PCR results demonstrated increased mRNA expressions of Nestin and β-catenin in the rats from the Shaoyao Gancaotang group （P<0.01）. Immunohistochemistry and western blot analyses indicated elevated protein expressions of Nestin and β-catenin in rats with SCA from the Shaoyao Gancaotang group （P<0.05， P<0.01）. ConclusionShaoyao Gancaotang may improve neurological function impairment and limb spasticity in model rats with SCA by regulating the proliferation and differentiation of neural stem cells in the cerebral cortex M1 region.