| Objective: To observe the changes in cognitive function and microglial polarization in AD rats treated with probiotics, and to preliminarily explore its mechanism of action, providing a theoretical basis for the rational use of probiotics. Methods: Ninety male rats were divided into three groups: sham operation group (n=30), model group, and model + probiotics group (n=30). The sham operation group was injected with sterile water into the bilateral hippocampal CA1 region of rats, while the model group was injected with Aβ1-42 into the bilateral hippocampal CA1 region. The model + probiotics group was
injected with Aβ1-42 into the bilateral hippocampal CA1 region and treated with probiotics by gavage. The cognitive function of each group of rats was evaluated. The changes of microglia (M1 and M2) in the cortex and hippocampus were detected by immunofluorescence. Primary microglia were isolated and cultured, and the expression of IBA1 was observed by immunofluorescence, and the phagocytic function was determined. Results: (1) The correct channel selection ability of the model + probiotics group was significantly enhanced in the Y-maze test compared with the model group, and the correct channel selection ability was significantly increased (P < 0.05); (2) The expression of IBA1 protein in the hippocampus of the sham operation group, model group and model + probiotics group was observed. The expression of IBA1 protein in the hippocampus of the model group was significantly increased, and the difference was statistically significant (P < 0.01). The laser confocal microscope was used to observe the cortex and hippocampus, showing that the expression of M1-type microglia in the cortex and hippocampus of the model group and probiotics group was significantly increased compared with the sham operation group, and the difference was statistically significant. Compared with the model group, the probiotics intervention group showed a significant increase in the number of M2-type microglia in the cortex and hippocampus, and the difference was statistically significant. The ratio of M1/M2-type microglia in the cortex and hippocampus of the probiotics group was significantly lower than that of the model group, and the difference was statistically significant; (3) The phagocytic function of microglia in the probiotics group was significantly stronger than that in the model group, and the difference was statistically significant (P < 0.05). Conclusion: Probiotics can improve the spatial exploration ability and working memory ability of rats, and enhance the phagocytic function of microglia. The mechanism may be to inhibit the transformation of M1 to M2-type microglia. |