| Summary: | 碩士 === 國立成功大學 === 醫學檢驗生物技術學系 === 104 === Folate, as known as vitamin B9, is a water-soluble nutrient which is essential for many physiological functions such as methylation, nucleotide synthesis and DNA repair. Folate deficiency (FD) had been reported as risk factor for neurological disease such as neuro tube defects and Alzheimer’s disease (AD). The role of FD in AD patients remains unclear. In the previous study, the deposition of β-amyloid (Aβ) and phosphorylated-tau, the pathological hallmarks of AD, were observed in the brain of aged FD zebrafish. The impaired cognitive ability was also observed in aged FD zebrafish. In this study, we investigated the impacts of folate status on the neuropathy of aged zebrafish. Simultaneously, aged zebrafish were tube feeding with either oxidized or reduced forms of folate and evaluated for their cognitive and memory ability. Then we measured the folate content in brain and liver, also applied immunohistochemistry staining in brain sections and then observed. The result showed that the tissue folate content was not significantly changed under the one-hour heat shock treatment, but the cognitive and memory ability of FD zebrafish was affected. The impairments were partially restored by supplementing with 5-formyltetrahydrofolate (5-CHO-THF) and lower dose (45 µg) of folic acid (FA). However, higher dose (400 µg) of FA, vitamin C, and ATP did not exert significant improvement. These findings suggested that supplementing with reduced folate and lower dose of FA had protective effect to the cognitive ability of aged zebrafish. To enhance the intensity of folate deficiency, we extended the heat shock treatment to 14 hours. The tissue folate content was significantly decreased in FD and the cognitive ability was also impaired. We found that the brain folate content was lower in cognitive ability impaired zebrafish. However, the result of Aβ deposition by the immunohistochemistry staining showed that there was no significant correlation between Aβ deposition and cognitive ability. Hence, we thought that the impact of FD on cognitive ability of aged zebrafish might not be due to Aβ deposition. In the future, the 8-OHdG stain was applied to investigate whether the oxidative stress in brain of zebrafish was affected by FD. Moreover, to examine the effect of other antioxidants and one-carbon provider on relieving the impairment of cognitive ability.
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