Plumbagin Ameliorate 5-Fluorouracil-Induced Cognitive Impairment in Adult Zebrafish: In-silico and In-vivo Evidences

Chemotherapy is a crucial part of cancer treatment, but it has been linked to a set of cognitive impairments. 5-Fluorouracil, a chemotherapeutic drug causing mitochondrial dysfunction and neurodegeneration. This study primarily aimed to evaluate the effect of Plumbagin on mitochondrial dynamics, neuroinflammation and oxidative stress in adult zebrafish subjected to 5-Fluorouracil-induced cognitive impairment.

In this study, initially in-silico studies were conducted for lead compound identification. For the in-vivo studies, adult zebrafish (~ 6-8 months old; 470-530 mg; 126 animals are used) were randomly assigned to 7 groups and treated with 5-Fluorouracil (25 mg/kg; i.p.) for 1 day followed by post-treated with Plumbagin (10 and 20 mg/kg; i.p.) and Donepezil (5 mg/kg; i.p.) for 6 days. Behavioral, biochemical, molecular, mitochondrial, and histopathological analyses were performed after completion of the study.

In-silico analyses revealed that Plumbagin exhibits stronger binding affinity as compared to 5-Fluorouracil. In vivo findings further demonstrated that post-treatment with Plumbagin significantly mitigates oxidative stress markers, reduces neuroinflammatory cytokines, and enhances mitochondrial functioning (mitochondrial enzyme complexes, caspases-3, and cellular viability) relative to zebrafish treated with 5-Flurouracil alone. Additionally, Plumbagin treatment led to marked reduction in GSK-3β expression, improvements in mitochondrial structure (as observed through Transmission electron microscopy analysis. Further, post-treatment with Plumbagin significantly improved mitochondrial morphology (as observed through TEM analysis) and neuronal morphology (assessed via Hematoxylin and Eosin staining and Nissl staining) as compared to 5-Fluorouracil -treated zebrafish.

Our findings provide strong evidence that Plumbagin significantly reduced neuroinflammation, provided neuroprotective support, and alleviates cognitive impairment, as demonstrated through in-silico and in-vivo analyses.