These changes led to several changes, including improving the slow movement and balance ability of mice, increasing the exploration ability of PD mice, decreasing astrocytes and microglia proportions in the substantia nigra, enhancing the number of neuronal synapses, lowering neuronal apoptosis, increasing the population of tyrosine hydroxylase-positive dopaminergic neurons in the substantia nigra, and increasing striatal tyrosine hydroxylase levels (Li et al., 2016). Here, TH is linked to Parkinson disease.