OBJECTIVE To explore the mechanism of kidney-tonifying and blood-activating recipe(Congrong Shujing granules) in ameliorating neuroinflammation in the substantia nigra-striatum of Parkinson's disease(PD) model mice.

METHODS PD model were established by intraperitoneal injection of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine(MPTP). The experimental group was divided into normal group, model group and treatment group. Behavioral tests were conducted on mice after the 7th day of modeling, as well as on the 7th and 14th day of treatment. The expression of tyrosine hydroxylase(TH) positive cells in the substantia nigra-striatum of mice was detected by immunohistochemistry(IHC). Mitochondrial morphology in substantia nigra-striatum neurons of mice was observed using transmission electron microscopy. Changes in intracellular reactive oxygen species(ROS) were analyzed by flow cytometry. Western blotting was performed to detect the expression of NLRP3, NOX2, Caspase-1(CASP1), IL-1β, and TNF-α proteins in the substantia nigra-striatum of mice.

RESULTS The behavioral study revealed that after 7 d of modeling, the duration of metal mesh hanging and movement in the core area in the model group was significantly reduced compared with normal group(P<0.001), while the time required to traverse the cross bar was significantly increased(P<0.001). Following 7 and 14 d of treatment, the duration of hanging and movement in the core area in the treatment group was significantly increased compared with model group(P<0.001), and the time required to traverse the cross bar was significantly reduced(P<0.01 or P<0.001). IHC analysis showed that, compared with the normal group, there was a significant reduction in the number of TH-positive cells in the substantia nigra of model group mice, while the treatment group showed a significant increase in TH-positive cells(P<0.001). Transmission electron microscopy revealed that, compared with the normal group, mitochondria of substantia nigra-striatum neurons of mice in the model group appeared swollen, vacuolated, and exhibited broken or absent cristae; these abnormalities were improved in the treatment group. Flow cytometry showed that intracellular ROS levels in the model group were significantly increased compared with normal group, but significantly decreased in the treatment group compared with model group(P<0.001). Western blotting analysis indicated that, compared with the normal group, the expressions levels of NLRP3, NOX2, CASP1, IL-1β and TNF-α proteins in the model group were significantly increased(P<0.01 or P<0.001), while their levels were significantly reduced in the treatment group compared with model group(P<0.05 or P<0.001).

CONCLUSION The kidney-tonifying and blood-activating recipe(Congrong Shujing granules) can ameliorate oxidative stress and neuroinflammatory responses in the substantia nigra-striatum of PD model mice, and this protective effect might be mediated via regulation of the NOX2/NLRP3/CASP1 signaling pathway.