OBJECTIVETo evaluate the changes of tumor necrosis factor-alpha (TNF-alpha) and nuclear factor-kappaB (NF-kappaB) expression in muscle of pressure ulcer rats and explore the relationship with apoptosis.

METHODSFifty-four male SD rats were randomly divided into nine groups (n = 6), the experiment groups were pressed 9 circles (3 circles/day, 3 days), then observed on the 1st, 3rd, hematoxylin and eosin staining under the microscope; the expression of TNF-alpha was detected by Western blot; the expressions of NF-kappaB and caspase-3 were determined by immunohistochemistry, and evaluated the relationship of TNF-alpha with NF-kappaB and caspase-3; the number of apoptotic cells in compressed muscle tissue was detected by Hoechst 33258 staining under the fluorescence microscope.

RESULTSCompared with the control group, histology examination showed that the tissue structure in experiment groups was in disorder, inter-space was wider, cell edema and the number of inflammatory cells were increased, the tissue was arranged in order and inflammatory cell recruitment was gradually attenuated. The expressions of TNF-alpha, NF-kappaB and caspase-3 were higher in the experiment groups than those in the control group (P < 0.05), reached their peak on the first day, gradually decreased on the 3nd day, but still had a significantly higher level than that in the control group (P < 0.01) on the 7th day; The number of apoptotic cells of experiment groups had a downward trend after the first rise under the fluorescence microscope; the expressions of TNF-alpha and NF-kappaB caspase-3 were found to have positive correlationship (P < 0.05), the expressions of NF-kappaB and caspase-3 were found to have positive correlationship (P < 0.01).

CONCLUSIONApoptosis is closely correlated with inflammation in deep tissue injury of pressure ulcer, NF-kappaB plays a role not only in the formation of inflammation, but also triggering apoptosis, which may induce the pathological change and clinical progress of pressure ulcer.