assessment of serum levels of phosphate and corticosterone as possible biomarkers for early diagnosis of parkinson’s disease in rats with 6-ohda-induced parkinson

Background: early diagnosis of parkinson›s disease can play an important role in improving its prognosis. due to controversies about the serum level of corticosterone and phosphate in parkinsonian rats, this study was designed to measure and evaluate the levels of corticosterone and phosphate as possible biomarkers of early diagnosis in rats with 6-ohda-induced parkinsonism.methods: forty rats were divided into three groups: control (n = 10), sham (n = 10), and 6-ohda (n = 20). the rats in the 6-ohda and sham groups underwent stereotaxic surgery to be injected with 6-ohda and its carrier into their medial forebrain bundle (mfb). apomorphine-induced rotational and cylinder tests were done to examine parkinsonism progression and sensory-motor function. corticosterone and phosphate serum levels were measured in the serum and striatum.results: net contralateral rotations and asymmetry scores in the fourth, sixth, and eighth weeks after surgery compared with the second week showed a gradual increase in the 6-ohda group. the serum levels of corticosterone were 90 ± 13 before surgery, and they declined to 88 ± 36 and 55 ± 9 ng/l in the second and eighth weeks after surgery, respectively. the serum levels of phosphate were 6 ± 0.22 before surgery, and they decreased to 5.2 ± 0.13 and 5 ± 0.12 mg/dl in the second and eighth weeks after surgery, respectively. the serum levels of phosphate and corticosterone remained relatively unchanged in the sham and control groups.conclusion: in conclusion, the progressive death of dopaminergic neurons is accompanied by decreased serum corticosterone and phosphate levels. thus, the serum level of corticosterone can be used as a biomarker in diagnosing parkinson’s disease. in contrast, serum phosphate levels were still within the normal range and cannot be used as a biomarker.