Psychological Stress Alters Ultrastructure and Energy Metabolism of Masticatory Muscle in Rats

[摘要] To investigate the effects of psychological stress on themasticatory muscles of rats, a communication box was applied toinduce the psychological stress (PS) in rats. The successfulestablishment of psychological stimulation was confirmed byelevated serum levels of adrenocorticotropic hormone (ACTH) andchanged behaviors in the elevated plusmaze apparatus. The energymetabolism of the bilateral masseter muscles was tested viachemocolorimetric analysis, whereas muscle ultrastructure wasassessed by electron microscopy. In comparison to the controlgroup, the PS group showed evidence of swollen mitochondria withcristae loss and reduced matrix density in the masticatory musclesafter three weeks of stimulation; after five weeks of stimulation,severe vacuolar changes to the mitochondria were observed. Increased vascular permeability of the masticatory musclecapillaries was found in the five-week PS rats. In addition, therewas decreased activity ofNa+-K+ATPase andCa2+-ATPase and asimultaneous increase in the activity of lactate dehydrogenase andlactic acid in the masticatory muscles of PS rats. Together, theseresults indicate that psychological stress induces alterations inthe ultrastructure and energy metabolism of masticatory muscles inrats.

[学科分类] 基础医学