METHODS: Adult zebrafish were divided into four groups: control, rotenone-treated, hMT2 pre-treatment, and hMT2 co-treatment. PD model was established by exposing zebrafish to 5 µg/L rotenone water for 28 days. hMT2 (0.2 µg) was administered intracranially either one day before or seven days after rotenone exposure.

RESULTS: The novel tank test demonstrated that rotenone exposure significantly impaired locomotor activity (p < 0.05) and increased anxiety-like behavior (p < 0.001). Additionally, PD model zebrafish exhibited reduced dopamine levels, decreased dopaminergic neuron population, elevated oxidative stress, heightened inflammatory response and mitochondrial dysfunction. Treatment with hMT2, especially in the co-treatment group, ameliorated these deficits by restoring locomotor activity, dopamine levels, and dopaminergic neuron counts while reducing oxidative stress and inflammation, and improving mitochondrial function.