To understand the potential paracrine roles of interleukin-1b (IL-1b), tumour necrosis factor-a(TNF-a) and interleukin-10 (IL-10), the expres-sion and secretion of these factors by rat bone marrow-derived mesenchy-mal cells stimulated by hypoxia (4% oxygen) and serum deprivation (hypoxia⁄SD) were investigated.