RESUMO
OBJECTIVE: To 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. METHODS: Fifty-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. RESULTS: Compared 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). CONCLUSION: Apoptosis 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.