Minocycline improves learning and memory functions in ischemic stroke rats via reduction of cerebral ischemia-induced neuroinflammation and apoptosis

Abstract

Purpose: To study the effect minocycline on learning and memory functions in ischemic stroke rats, and the underlying mechanism. Methods: 60 adult male SD rats were randomly divided into control group, ischemic brain damage (6 and 24 h MACO) groups; and 6 and 24 h minocycline groups, with 12 rats in each group. The volume of cerebral infarction, neuronal cell apoptosis, NF-κB protein expression, learning and memory ability, and the number of Iba-1+CD206-positive cells, and CD206/CD68 mRNA expressions in sham group, 6 h MACO group and 6 h minocycline group were determined and compared. Results: The number of iba-1 +CD206-positive cells, expression level of CD206 mRNA, frequency of platform crossing, and percentage of third quadrant route in 6 h minocycline group were significantly higher than the corresponding values in 6 h MACO group. However, the cerebral infarction volume, number of Nini-positive cells, and the NF- B protein expression levels were markedly reduced, relative to corresponding values in 6 h MACO rats. The number of iba-1+CD206-positive cells was significantly lower in 6 h MACO rats than in sham rats, while the expression level of CD68 mRNA was significantly higher (p < 0.05). The number of TUNEL-positive cells in 6 and 24 h minocycline groups were markedly lower than that in 6 h MACO group (p < 0.05). Conclusion: Minocycline improves learning and memory of ischemic stroke rats by relieving the neuroinflammation induced by cerebral ischemia and cell apoptosis. Thus, the compound can be further developed for management learning and memory deficits in stroke patients.