[Overwork induces vascular endothelial barrier dysfunction in mice].

Objective: To investigate the impact of overwork on vascular endothelial barrier function in mice.

Methods: Thirty KM mice were randomized equally into control, overwork for 2 weeks (W2) group and 4 weeks (W4) group. In the latter two groups, the mice were subjected to continuous standing in water for 8 h followed by restraint for 3 h to simulate overwork on a daily basis for 2 and 4 weeks. After modeling, 4 mice from each group were intraperitoneally injected with Evans blue dye to assess vascular permeability. In the other 6 mice, serum IL-1β levels were measured using ELISA, and arterial tissues were collected for histological examination and detection of mRNA expressions of occludin, claudin-5, ZO-1, JAM-A and VE-cadherin; immunofluorescence assay was used to detect the protein expressions of claudin-5, ZO-1, VE-cadherin, and Syndecan-1.

Results: The mice in W2 and W4 groups exhibited slower weight gain, hair loss, reduced activity, and significantly increased serum IL-1β levels. Vascular permeability was significantly increased in W4 group. In W2 group, the endothelial cells were swollen and dissociated, and the intima was rough and irregular; arterial intimal rupture was observed in W4 group. The mRNA expressions of occludin, claudin-5, ZO-1 and JAM-A in the arterial tissues were significantly increased in W2 group but decreased in W4 group, while VE-cadherin mRNA expression were reduced in both groups (P < 0.05). The protein expressions of claudin-5, ZO-1, VE-cadherin, and Syndecan-1 were all significantly reduced in W4 group.

Conclusion: Prolonged overwork can cause damage of the intercellular junction complexes in arterial endothelial cells and the endothelial glycocalyx to result in impaired barrier function and increased vascular permeability in mice.