Background: The inhibition of matrix metalloproteinases (MMPs) has shown potential in the treatment of various neurodegenerative diseases, and perioperative neurocognitive disorders (PND) is accompanied by the increased expression of MMP-2 and MMP-9 in the hippocampus. However, the effect of inhibiting MMP-2 and MMP-9 on PND is not clear. In this study we aimed to evaluate the effects of inhibiting MMP-2 and MMP-9 on cognitive function in the aged mice after surgery, in order to find a possible target for the prevention and treatment of PND METHODS: In this study, 14-month-old C57BL/6 mice were used to establish a PND model by tibial fracture surgery and sevoflurane anesthesia. Three days later, part of the mice were subjected to cognitive assessment and the other was sacrificed for biochemical analysis. We used the Novel object recognition test and Fear conditioning test to evaluate the postoperative cognitive function of mice. The expression of mmp-2 and MMP-9 was detected by western blotting. We also examined the expression of claudin-5 and occludin using Western blotting, and the activation of microglia and astrocytes using immunofluorescence.
Results: The results showed that surgery increased the expression of MMP-2 and MMP-9 in the hippocampus of mice, accompanied by cognitive impairment, decreased expression of claudin-5 and occludin, and increased activation of microglia and astrocytes. However, inhibition of MMP-2 and MMP-9 expression by SB-3CT reversed these changes.
Conclusions: Our study shows that inhibition of MMP-2 and MMP-9 alleviates anesthesia/surgery-induced cognitive decline by increasing BBB integrity and inhibiting glial cell activation.
Keywords: Aged mice; Blood-brain barrier; Matrix metalloproteases; Neuroinflammation; Perioperative neurocognitive disorder.
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