Long-term Levodopa Treatment Accelerates the Circadian Rhythm Dysfunction in a 6-hydroxydopamine Rat Model of Parkinson's Disease / 中华医学杂志(英文版)
Chinese Medical Journal
;
(24): 1085-1092, 2017.
Article
in English
| WPRIM
| ID: wpr-266857
ABSTRACT
<p><b>BACKGROUND</b>Parkinson's disease (PD) patients with long-term levodopa (L-DOPA) treatment are suffering from severe circadian dysfunction. However, it is hard to distinguish that the circadian disturbance in patients is due to the disease progression itself, or is affected by L-DOPA replacement therapy. This study was to investigate the role of L-DOPA on the circadian dysfunction in a rat model of PD.</p><p><b>METHODS</b>The rat model of PD was constructed by a bilateral striatal injection with 6-hydroxydopamine (6-OHDA), followed by administration of saline or 25 mg/kg L-DOPA for 21 consecutive days. Rotarod test, footprint test, and open-field test were carried out to evaluate the motor function. Striatum, suprachiasmatic nucleus (SCN), liver, and plasma were collected at 600, 1200, 1800, and 2400. Quantitative real-time polymerase chain reaction was used to examine the expression of clock genes. Enzyme-linked immunosorbent assay was used to determine the secretion level of cortisol and melatonin. High-performance liquid chromatography was used to measure the neurotransmitters. Analysis of variance was used for data analysis.</p><p><b>RESULTS</b>L-DOPA alleviated the motor deficits induced by 6-OHDA lesions in the footprint and open-field test ( P < 0.01, P < 0.001, respectively). After L-DOPA treatment, Bmal1 decreased in the SCN compared with 6-OHDA group at 1200 ( P < 0.01) and 2400 ( P < 0.001). In the striatum, the expression of Bmal1, Rorα was lower than that in the 6-OHDA group at 1800 (P < 0.05) and L-DOPA seemed to delay the peak of Per2 to 2400. In liver, L-DOPA did not affect the rhythmicity and expression of these clock genes (P > 0.05). In addition, the cortisol secretion was increased (P > 0.05), but melatonin was further inhibited after L-DOPA treatment at 600 (P < 0.01).</p><p><b>CONCLUSIONS</b>In the circadian system of advanced PD rat models, circadian dysfunction is not only contributed by the degeneration of the disease itself but also long-term L-DOPA therapy may further aggravate it.</p>
Full text:
Available
Index:
WPRIM (Western Pacific)
Main subject:
Body Weight
/
Enzyme-Linked Immunosorbent Assay
/
Levodopa
/
Blotting, Western
/
Fluorescent Antibody Technique
/
Circadian Rhythm
/
Oxidopamine
/
Rats, Sprague-Dawley
/
Therapeutic Uses
/
Toxicity
Limits:
Animals
Language:
English
Journal:
Chinese Medical Journal
Year:
2017
Type:
Article
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