**6. Conclusions**

Occludin, as a cellular tight junction protein, mediates molecular communication between cells and maintains the integrity of various tissues and cells. More and more studies have confirmed that under pathological conditions, various signaling pathways can disrupt the integrity of cell barrier by regulating the expression and distribution of occludin, and participate in apoptosis, inflammation, cardiovascular and neurodegenerative diseases. Occludin plays an important role in cardiovascular disease, but current research also faces great challenges. A variety of classical signaling pathways can regulate the expression and distribution of occludin, but only some studies suggest that occludin can act as an upstream regulatory molecule to affect downstream signaling pathways, whether it affects multiple molecules and signaling pathways is an urgent problem to be solved. At present, most researches focus on occludin participating in cell barrier and maintaining cell integrity. Whether its overexpression plays a positive role in all systems is unknown. Loss of occludin can affect vascular endothelial permeability, leading to pathology such as inflammatory cell infiltration, apoptosis, and oxidative stress. However, whether inflammatory stimulation, apoptosis, and oxidative stress can directly affect the expression, modification, and redistribution of occludin is the current vacancy in current research field and needs further exploration and discovery. Relatively speaking, the research on occludin and vascular endothelial injury-related diseases is still very limited, but there is already relevant evidence that it is a close relationship between them. There is still a large gap in the relationship between occludin and vascular metabolic diseases needs to be filled. With further research in the future, the connection between occludin and many diseases related to vascular endothelial injury will become increasingly clear. In a word, whether it is possible to inhibit or use occludin to develop related drugs and apply them to the treatment of clinical diseases requires further research and discovery.
