Effects of Hypoxia/reoxygenation and Cytokines on Adhesion of Leukocytes to Cerebral Microvascular Endothelial Cells

Aim: To study the influence of hypoxia/reoxygenation (H/R) on the adhesion of neutrophils (Neu) and monocytes (Mon) to cultured bovine cerebral microvascular cells induced by tumor necrosis factor alpha (TNF-alpha) or interleukin 1-alpha (IL-1 alpha).

Methods: Bovine cerebral microvascular endothelial cells (CMEC) and smooth muscle cells (CMSMC) were exposed to normoxia or H/R in the presence or absence of TNF-alpha (IL-1 alpha). The number of adhesions of Mon and Neu to CMEC and CMSMC was measured by flow cytometry.

Results: CMEC were subjected to hypoxia for 2 h followed by reoxygenation with TNF-alpha (2 micrograms.L-1) for 2 h, the adhesion rate of CMEC for Mon and Neu were increased to 35.0% +/- 0.9% and 36.0% +/- 0.6% (the TNF-alpha treated group was 28.9% +/- 1.1% and 28.8% +/- 1.3%), respectively. CMSMC were treated as above, the adhesion rate of Mon and Neu was enhanced to 49.9% +/- 0.4% and 43.9% +/- 1.4% (the TNF-alpha treated group was 34.0% +/- 1.9% and 34.0% +/- 1.3%), respectively. CMEC and CMSMC were treated by IL-1 alpha, similar results were obtained.

Conclusion: H/R enhanced the adhesion of Mon and Neu to CMEC and CMSMC induced by TNF-alpha or IL-1 alpha.