Effects of Urolithin A on Climbing Performance in Adult Drosophila melanogaster and Early Morphological Development in Danio rerio Embryos: A Pilot Study

Mitochondrial dysfunction(definition) contributes to many age-related diseases, including Alzheimer’s and Parkinson’s disease. Urolithin A can activate mitophagy in mammals, but less is known about its effects in simpler model organisms. This pilot study investigated whether fruit flies (Drosophila melanogaster) and zebrafish (Danio rerio) embryos could serve as baseline models for evaluating the biological effects of urolithin A. Zebrafish embryos were treated with urolithin A for 5 days, while adult flightless flies were fed urolithin A at a nominal 0.221 mg/mL and assessed using a climbing assay. Fly counts were obtained using an AI-assisted image analysis tool. No visible morphological differences were observed in the zebrafish embryos. Mitophagy was not directly measured in either organism. No fly crossed the 6 cm threshold before 10 seconds, and only three crossings were recorded, across 44 fly-session observations in the treated vials and 16 in the control vials, at 10 and 12 seconds. Both untreated control sessions had no crossings at any recorded time point. Although all three observed crossings occurred in treated flies, the small sample size and experimental limitations prevented these observations from supporting a treatment effect. The zebrafish hypothesis was supported only in the narrow sense that no visible abnormalities were detected. This study did not provide enough evidence to establish either organism as a reliable baseline model. The distribution of crossing times indicates that the scoring window used was too short to capture most climbing. Larger studies using aging or disease models and direct measures of mitochondrial function are needed.