OBJECTIVE  To explore the molecular mechanism of Compound Dihuang Granule in treating Parkinson's disease (PD) with yin-deficiency and dynamic wind syndrome by regulating the changes of ubiquitin-proteasome system-related proteins.

  METHODS  SPF male SD rats were randomly selected as normal control group and sham operation group, 13 rats in each group. The remaining rats were treated with 6-hydroxydopamine lateral brain injection to damage the substantia nigra to establish PD yin-deficiency and dynamic wind syndrome rat model. The established rats were randomly divided into model group, madopar group (150 mg·kg^-1), low, medium and high dose groups of Compound Dihuang Granule (1.75, 3.5, 7 g·kg^-1), 13 rats in each group. Each group was given drugs by intragastric gavage for 28 d. The general conditions and neurobehavioral manifestations of the rats were observed; the expression of ubiquitin (UB), ubiquitin activating enzyme (UBE1), ubiquitin conjugating enzyme (UBE2A) and ubiquitin carboxyl terminal hydrolase (UCH-L1) positive cells, protein and mRNA expression levels in the damaged lateral striatum of the brain of rats were detected by immunohistochemistry, Western blot and qPCR methods; changes of dopamine (DA) content in the damaged lateral striatum of the brain of rats were detected by ELISA.

  RESULTS  There was no significant difference in general conditions between the normal control group and the sham operation group, and there was no significant difference in the number of rotations, suspension time and number of moving grids. Compared to the sham-op group, the model group rats showed poor spirit, irritability, limb tremor, slow movement, dark yellow fur, less food intake, reduced body weight; the modeling increased number of rotations, decreased hanging time and number of moving grids (P < 0.01), significantly decreased expression of UB, UBE1, UBE2A, and UCH-L1 positive cells, mRNA and protein expression levels in the damaged lateral striatum (P < 0.01), and significantly decreased DA content (P < 0.01). Compared with the model group, the general condition of the rats in the madopar group and Compound Dihuang Granule groups was improved, the number of rotations was reduced, the hanging time and number of moving grids were increased (P < 0.05, P < 0.01), the expression of UB, UBE1, UBE2A, and UCH-L1 positive cells, mRNA and protein expression levels were increased (P < 0.05, P < 0.01), and the DA content was increased (P < 0.01); behavioral tests and the expression levels of various indicators were most significantly improved in the madopar group and the high-dose Compound Dihuang Granule group (P < 0.05, P < 0.01), and there was no statistical significance between the two groups.

  CONCLUSION  Compound Dihuang Granule may play a role in treating PD yin-deficiency and dynamic wind syndrome by regulating the expression of ubiquitin-proteasome system-related proteins, reducing abnormal protein aggregation, and thus alleviating DA content deficiency, and the high-dose Compound Dihuang Granule has the best effect.