Effects of pressor stimulation at different times on rat skeletal muscle morphology and tumor necrosis factor alpha and nuclear factor kappaB
BACKGROUND:Studies have shown that different durations of pressure application on normal muscles can produce varying physiological responses.OBJECTIVE:To explore the expression levels of inflammatory factors tumor necrosis factor α and nuclear κB in skeletal muscle under different pressure durations.METHODS:Twenty healthy male SPF-grade Sprague-Dawley rats were randomly divided into four groups:control group,10-second pressure group,20-second pressure group,and 30-second pressure group.The right leg of each rat was used for the experiment.The control group received no intervention,while rats in each pressure group were anesthetized by intraperitoneal injection of 2%pentobarbital sodium(35 mg/kg),and the thin femoral muscle of the rats was pressed continuously at a constant pressure of 200 kPa using a homemade mechanical pressure device for 10,20,and 30 seconds,respectively.Muscle tissue at the pressing site of the right hind limb was collected immediately after pressure.Hematoxylin-eosin staining was used to observe the morphological changes of skeletal muscle tissues and changes in the cross-sectional area of muscle fibers,and immunohistochemistry was used to detect the expression levels of tumor necrosis factor α and nuclear factor κB in rat skeletal muscle.RESULTS AND CONCLUSION:Hematoxylin-eosin staining results revealed that the pressure groups showed loosely arranged skeletal muscle fibers,reduced cross-sectional area and diameter,and enlarged intermuscular spaces.Compared with the control group,the cross-sectional area of muscle fibers was significantly reduced in the pressure groups(P<0.05),but there was no significant difference between the three pressure groups(P>0.05).The 10-second pressure group showed no significant presence of red blood cells in the interstitial spaces,while the 20-second pressure group exhibited a small amount of red blood cells,and the 30-second pressure group showed capillary dilation with red blood cells in the interstitial spaces.The expression level of tumor necrosis factor α in the 30-second pressure group was significantly higher than that in the control group(P<0.05).The expression level of nuclear factor κB in skeletal muscle showed no significant difference among groups(P>0.05).To conclude,skeletal muscle undergoes morphological changes and reduced cross-sectional area after pressure at 200 kPa,but there is no significant difference among the 10-,20-,and 30-second pressure groups.As the duration of pressure increases to 30 seconds,the inflammatory factor tumor necrosis factor α is activated,but nuclear factor κB remains unaffected,suggesting that inflammatory factors may express under short-term pressure,while transcription factors show no significant change.
万方数据
维普
