TH and Parkinson disease: Other studies have determined by immunoblotting that irisin rescues dopamine transporter protein (DAT)-positive and tyrosine hydroxylase (TH)-positive fibers, prevented the loss of dopamine neurons and lowering of striatal dopamine (Kam et al., 2022), and effectively promotes dopamine absorption in the contralateral striatum of the affected limb in PD patients (Shi et al., 2024).