Targeted Antioxidant, Catalase–SKL, Reduces Beta-Amyloid Toxicity in the Rat Brain

Accumulation of beta-amyloid (Aβ) in the brain has been implicated as a major contributor to the cellular pathology and cognitive impairment observed in Alzheimer's disease. Beta-amyloid may exert its toxic effects by increasing reactive oxygen species and neuroinflammation in the brain. This study set out to investigate whether a genetically engineered derivative of the peroxisomal antioxidant enzyme catalase (CAT–SKL), is able to reduce the toxicity induced by intracerebroventricular injection of Aβ_25–35 in the mature rat brain. Histopathological and immunohistochemical analyses were used to evaluate neuroinflammation, and neuronal loss. Spatial learning and reference memory was assessed using the Morris water maze. CAT–SKL treatment was able to reduce the pathology induced by Aβ_25-35 toxicity by significantly decreasing microglia activation in the basal forebrain and thalamus, and reducing cholinergic loss in the basal forebrain. Aβ_25–35 animals showed deficits in long-term reference memory in the Morris water maze, while Aβ_25–35 animals treated with CAT–SKL did not demonstrate long-term memory impairments. This preclinical data provides support for the use of CAT–SKL in reducing neuroinflammation and long-term reference memory deficits induced by Aβ_25–35.