Early diagnosis of Parkinson's disease can play important role on the progression of the disease. Due to controversies about Corticosterone and phosphate, this study was designed to measure the level of Corticosterone and phosphate in rats with 6-OHDA-induced Parkinson's disease.
Materials and methods:
Forty rats were divided into three groups, Control (n=10), sham (n=10), and 6-OHDA group (n=20). Rats in 6-OHDA and Sham group underwent surgery for injection of 6-OHDA and ascorbic acid solution as the carrier. Behavioral tests and blood sampling were performed, and ELISA and colorimetric methods measured the level of Corticosterone and phosphate.
The intensity of rotational behavior increased after surgery in the 6-OHDA group by 63, 88, and 163% in the fourth, sixth, and eighth weeks after surgery compared with the second week. Levels of Corticosterone in the 6-OHDA group before surgery and second and eighth weeks after surgery were 90±13, 88±36, 55±9 ng/L. Levels of phosphate in the 6-OHDA group before surgery and second and eighth weeks after surgery were 6±0.22, 5.2±0.13, 5±0.12 mg/dl.
Our study revealed that progressive death of dopaminergic neurons in the striatum is associated with decreased levels of Corticosterone, but it was not observed in the early stages from mild to moderate neuronal degeneration. Although phosphate levels decreased, the reduced phosphate levels were in the normal range. Neither serum levels of Glucocorticoids nor phosphate can be used as biomarkers in the early diagnosis of Parkinson.