Effects of lateral cerebellar nucleus lesion on motor coordination and neurovascular remodeling in rats

The lateral cerebellar nucleus plays a critical role in the regulation of distal motor coordination and integration of learned motor responses. The present study investigated the functional consequences of unilateral lesion of the lateral cerebellar nucleus in rats and evaluated the effects of bacterial melanin on recovery processes. Adult rats were trained to perform a balance-dependent motor task on a rotating rod, followed by stereotaxic lesion of the nucleus. Animals were randomly assigned to receive either bacterial melanin or saline and were assessed daily over a 45-day period. Lesion of the lateral cerebellar nucleus resulted in marked impairment of distal motor coordination, with latency to fall reduced from 236 ± 8 s to markedly reduced values on the first postoperative day. In control animals, restoration of coordinated hindlimb movement required 40 ± 1.2 days, whereas melanin-treated animals recovered within 5 ± 1.2 days, corresponding to a mean difference of − 35 days (95% CI − 36.54 to − 33.46, p < 0.001). Histological analysis demonstrated a 48% reduction in astrocytic activation, a 35% increase in capillary density, and a 42% increase in axonal branching in treated animals (p < 0.01). Vascular endothelial growth factor levels were elevated, while pro-inflammatory cytokines and lipid peroxidation markers were reduced, accompanied by increased antioxidant enzyme activity. These findings suggest that bacterial melanin is associated with accelerated functional recovery, potentially through modulation of gliosis, angiogenesis, and oxidative balance following cerebellar injury.