Insights into Vincristine-Induced Peripheral Neuropathy in Aged Rats: Wallerian Degeneration, Oxidative Damage, and Alterations in ATPase Enzymes

This study aimed to elucidate vincristine (VCR)-induced peripheral neuropathy in aged rats, a poorly understood neurotoxicity. Both young and old Wistar rats were administered VCR (0.1 mg/kg, intraperitoneally (i.p.)) and compared to age-matched controls (0.9% saline; 10 mg/mL, i.p.). Mechanical (MN) and thermal nociceptive (TN) responses were assessed on days 0, 6, 11, and 17. Locomotor response, cognitive ability, and anxious-like behavior were evaluated on days 14, 15, and 16. Results showed MN and TN responses in both young and old VCR-exposed rats. In old rats, VCR exacerbated MN (on days 6, 11, and 17) and TN (on days 6 and 17) responses. VCR also induced cognitive impairments and anxiety-like behavior. Histological analysis revealed Wallerian degeneration in the spinal cords of VCR-exposed rats accompanied by macrophage migration. Furthermore, VCR increased Ca²⁺-ATPase activity while inhibiting Na⁺, K⁺-ATPase activity in young and old rats. VCR altered the homeostasis of Mg²⁺-ATPase activity. Lipid peroxidation and nitrite and nitrate levels increased in young and old rats exposed to VCR. This study provides valuable insights into VCR's mechanistic pathways in aged rats, emphasizing the need for further research in this area.