Aims: Parkinson's disease (PD), a chronic neurological disorder affecting motor functions, is characterized by damage to dopaminergic neurons in the substantia nigra pars compacta (SNc). This study investigates the therapeutic properties of bacterial melanin (BM), known for enhancing brain trophic effects, inhibiting inflammation, and mitigating gliosis—a key aspect in PD development.Methods: To assess rat brain morpho-functional states, we conducted histochemical and morphometric studies on SNc cellular structures post-rotenone intoxication and under BM influence. Experiments involved intact rats, a PD model 4 weeks after rotenone injection, and a PD model with 4 weeks of BM injections. Morphohistochemical analysis identified Ca2+-dependent acid phosphatase activity, while Chilingaryan's non-injection histoangiological method detected microvasculature.Results: In the rotenone-induced PD model, severe depigmentation, intracellular structural changes, atrophy, and reduced phosphatase activity were observed, alongside PD-like behavior in the behavioral test (cylinder test). BM positively influenced SNc neuron structure towards normalcy, activating cellular metabolic processes. In rotenone-intoxicated rats, BM restored capillary dimensions and the network, enhancing trophic actions. This intervention increased capillary density, ensuring nerve cell safety. Improved animal behavior indicators further suggest a positive outcome, emphasizing BM's neuroprotective potential in the context of rotenone-induced intoxication.Conclusions: Thus, BM possesses vasodilating and angioprotective properties on capillaries, contributing to its neuroprotective impact on SNc neurons. These effects are associated with improved microcirculation and accelerated compensatory recovery, countering neurodegenerative changes inherent in PD.The work was supported by the Science Committee of RA, in the frames of the research project №21T-1F282.