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Psychological stress alters ultrastructure and energy metabolism of masticatory muscle in rats.

Chen YJ, Huang F, Zhang M, Shang HY - J. Biomed. Biotechnol. (2010)

Bottom Line: The successful establishment of psychological stimulation was confirmed by elevated serum levels of adrenocorticotropic hormone (ACTH) and changed behaviors in the elevated plusmaze apparatus.The energy metabolism of the bilateral masseter muscles was tested via chemocolorimetric analysis, whereas muscle ultrastructure was assessed by electron microscopy.In comparison to the control group, the PS group showed evidence of swollen mitochondria with cristae loss and reduced matrix density in the masticatory muscles after three weeks of stimulation; after five weeks of stimulation, severe vacuolar changes to the mitochondria were observed.

View Article: PubMed Central - PubMed

Affiliation: Department of General Dentistry and Emergency, School of Stomatology, The Fourth Military Medical University, Xi'an, Shanxi 710032, China. cyj1229@fmmu.edu.cn

ABSTRACT
To investigate the effects of psychological stress on the masticatory muscles of rats, a communication box was applied to induce the psychological stress (PS) in rats. The successful establishment of psychological stimulation was confirmed by elevated serum levels of adrenocorticotropic hormone (ACTH) and changed behaviors in the elevated plusmaze apparatus. The energy metabolism of the bilateral masseter muscles was tested via chemocolorimetric analysis, whereas muscle ultrastructure was assessed by electron microscopy. In comparison to the control group, the PS group showed evidence of swollen mitochondria with cristae loss and reduced matrix density in the masticatory muscles after three weeks of stimulation; after five weeks of stimulation, severe vacuolar changes to the mitochondria were observed. Increased vascular permeability of the masticatory muscle capillaries was found in the five-week PS rats. In addition, there was decreased activity of Na(+)-K(+)ATPase and Ca(2+)-ATPase and a simultaneous increase in the activity of lactate dehydrogenase and lactic acid in the masticatory muscles of PS rats. Together, these results indicate that psychological stress induces alterations in the ultrastructure and energy metabolism of masticatory muscles in rats.

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Measurement of rat behaviors in the elevated plus-maze test. Comparison of the percentage of open arm entries (OE%) (a) and the percentage of time spent in the open arms (OT%) (b) in the EPM test among groups. Data were expressed as  SE and analyzed in eight rats from each group (*P < .05, PS group versus CON group).
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fig3: Measurement of rat behaviors in the elevated plus-maze test. Comparison of the percentage of open arm entries (OE%) (a) and the percentage of time spent in the open arms (OT%) (b) in the EPM test among groups. Data were expressed as SE and analyzed in eight rats from each group (*P < .05, PS group versus CON group).

Mentions: We then compared the behaviors of rats after three or five weeks of psychological stimulation with those of the control group by EPM tests. As shown in Figure 3(a), percentages (%) of entry into open arms (open arm entry, OE) in the PS rats were 34.02 ± 2.89% and 24.66 ± 1.99% after three or five weeks of stimulation, respectively, while those of control group were 48.94 ± 2.94% and 48.65 ± 3.81%, respectively, which were significantly higher than the PS groups. Similarly, as shown in Figure 3(b), percentages of time spent in open arms (OT%) significantly decreased from 70.39 ± 3.03% in the control group to 46.14 ± 4.05% in the PS group after three weeks of psychological stimulation and from 72.25 ± 1.35% in the control group to 25.05 ± 3.07% in PS group after five weeks (P < .05), indicating that the rats in PS group were mentally under tension.


Psychological stress alters ultrastructure and energy metabolism of masticatory muscle in rats.

Chen YJ, Huang F, Zhang M, Shang HY - J. Biomed. Biotechnol. (2010)

Measurement of rat behaviors in the elevated plus-maze test. Comparison of the percentage of open arm entries (OE%) (a) and the percentage of time spent in the open arms (OT%) (b) in the EPM test among groups. Data were expressed as  SE and analyzed in eight rats from each group (*P < .05, PS group versus CON group).
© Copyright Policy - open-access
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2968718&req=5

fig3: Measurement of rat behaviors in the elevated plus-maze test. Comparison of the percentage of open arm entries (OE%) (a) and the percentage of time spent in the open arms (OT%) (b) in the EPM test among groups. Data were expressed as SE and analyzed in eight rats from each group (*P < .05, PS group versus CON group).
Mentions: We then compared the behaviors of rats after three or five weeks of psychological stimulation with those of the control group by EPM tests. As shown in Figure 3(a), percentages (%) of entry into open arms (open arm entry, OE) in the PS rats were 34.02 ± 2.89% and 24.66 ± 1.99% after three or five weeks of stimulation, respectively, while those of control group were 48.94 ± 2.94% and 48.65 ± 3.81%, respectively, which were significantly higher than the PS groups. Similarly, as shown in Figure 3(b), percentages of time spent in open arms (OT%) significantly decreased from 70.39 ± 3.03% in the control group to 46.14 ± 4.05% in the PS group after three weeks of psychological stimulation and from 72.25 ± 1.35% in the control group to 25.05 ± 3.07% in PS group after five weeks (P < .05), indicating that the rats in PS group were mentally under tension.

Bottom Line: The successful establishment of psychological stimulation was confirmed by elevated serum levels of adrenocorticotropic hormone (ACTH) and changed behaviors in the elevated plusmaze apparatus.The energy metabolism of the bilateral masseter muscles was tested via chemocolorimetric analysis, whereas muscle ultrastructure was assessed by electron microscopy.In comparison to the control group, the PS group showed evidence of swollen mitochondria with cristae loss and reduced matrix density in the masticatory muscles after three weeks of stimulation; after five weeks of stimulation, severe vacuolar changes to the mitochondria were observed.

View Article: PubMed Central - PubMed

Affiliation: Department of General Dentistry and Emergency, School of Stomatology, The Fourth Military Medical University, Xi'an, Shanxi 710032, China. cyj1229@fmmu.edu.cn

ABSTRACT
To investigate the effects of psychological stress on the masticatory muscles of rats, a communication box was applied to induce the psychological stress (PS) in rats. The successful establishment of psychological stimulation was confirmed by elevated serum levels of adrenocorticotropic hormone (ACTH) and changed behaviors in the elevated plusmaze apparatus. The energy metabolism of the bilateral masseter muscles was tested via chemocolorimetric analysis, whereas muscle ultrastructure was assessed by electron microscopy. In comparison to the control group, the PS group showed evidence of swollen mitochondria with cristae loss and reduced matrix density in the masticatory muscles after three weeks of stimulation; after five weeks of stimulation, severe vacuolar changes to the mitochondria were observed. Increased vascular permeability of the masticatory muscle capillaries was found in the five-week PS rats. In addition, there was decreased activity of Na(+)-K(+)ATPase and Ca(2+)-ATPase and a simultaneous increase in the activity of lactate dehydrogenase and lactic acid in the masticatory muscles of PS rats. Together, these results indicate that psychological stress induces alterations in the ultrastructure and energy metabolism of masticatory muscles in rats.

Show MeSH
Related in: MedlinePlus