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Regional differences in expression of VEGF mRNA in rat gastrocnemius following 1 hr exercise or electrical stimulation.

Brutsaert TD, Gavin TP, Fu Z, Breen EC, Tang K, Mathieu-Costello O, Wagner PD - BMC Physiol. (2002)

Bottom Line: A greater upregulation in oxidative regions was hypothesized.These regional differences were not significantly different from control muscle (non-exercised, non-stimulated, N = 2 muscles), although nearly so for electrically stimulated muscle (P = 0.056).However, it is not possible to determine if the VEGF mRNA signal difference is important in either the maintenance of regional capillarity differences or exercise induced angiogenesis.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Physiology, School of Medicine, University of California, San Diego 92093-0623A, USA. tbrutsae@csc.albany.edu

ABSTRACT

Background: Vascular endothelial growth factor (VEGF) mRNA levels increase in rat skeletal muscle after a single bout of acute exercise. We assessed regional differences in VEGF165 mRNA levels in rat gastrocnemius muscle using in situ hybridization after inducing upregulation of VEGF by treadmill running (1 hr) or electrical stimulation (1 hr). Muscle functional regions were defined as oxidative (primarily oxidative fibers, I and IIa), or glycolytic (entirely IIb or IId/x fibers). Functional regions were visualized on muscle cross sections that were matched in series to slides processed through in situ hybridization with a VEGF165 probe. A greater upregulation in oxidative regions was hypothesized.

Results: Total muscle VEGF mRNA (via Northern blot) was upregulated 3.5-fold with both exercise and with electrical stimulation (P = 0.015). Quantitative densitometry of the VEGF mRNA signal via in situ hybridization reveals significant regional differences (P

Conclusions: Moderately higher VEGF mRNA signal in oxidative muscle regions is consistent with regional differences in capillary density. However, it is not possible to determine if the VEGF mRNA signal difference is important in either the maintenance of regional capillarity differences or exercise induced angiogenesis.

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Related in: MedlinePlus

Representative Northern blot for total VEGF mRNA levels. (A) resting, (B) exercised, and (C) electrically stimulated gastrocnemius muscles. Blots were reprobed and normalized to 18S ribosomal RNA (18S).
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Figure 2: Representative Northern blot for total VEGF mRNA levels. (A) resting, (B) exercised, and (C) electrically stimulated gastrocnemius muscles. Blots were reprobed and normalized to 18S ribosomal RNA (18S).

Mentions: Figure 2 shows representative Northern blots for total VEGF mRNA levels examined in (A) resting control, (B) exercised, and (C) electrically stimulated muscles. It is clear that VEGF mRNA levels are elevated over resting after both 1 hour of treadmill exercise and 1 hour of electrical stimulation. This is shown clearly in Figure 3 which gives the quantitative densitometry for VEGF mRNA, normalized to 18S ribosomal RNA. A significant increase in VEGF mRNA over resting control is observed after 1 hour of treadmill running (~3.5-fold, P = 0.015), and after 1 hour of electrical stimulation (~3.5-fold, P = 0.015). There were no significant differences in the VEGF mRNA levels between exercised and electrically stimulated muscles.


Regional differences in expression of VEGF mRNA in rat gastrocnemius following 1 hr exercise or electrical stimulation.

Brutsaert TD, Gavin TP, Fu Z, Breen EC, Tang K, Mathieu-Costello O, Wagner PD - BMC Physiol. (2002)

Representative Northern blot for total VEGF mRNA levels. (A) resting, (B) exercised, and (C) electrically stimulated gastrocnemius muscles. Blots were reprobed and normalized to 18S ribosomal RNA (18S).
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC117122&req=5

Figure 2: Representative Northern blot for total VEGF mRNA levels. (A) resting, (B) exercised, and (C) electrically stimulated gastrocnemius muscles. Blots were reprobed and normalized to 18S ribosomal RNA (18S).
Mentions: Figure 2 shows representative Northern blots for total VEGF mRNA levels examined in (A) resting control, (B) exercised, and (C) electrically stimulated muscles. It is clear that VEGF mRNA levels are elevated over resting after both 1 hour of treadmill exercise and 1 hour of electrical stimulation. This is shown clearly in Figure 3 which gives the quantitative densitometry for VEGF mRNA, normalized to 18S ribosomal RNA. A significant increase in VEGF mRNA over resting control is observed after 1 hour of treadmill running (~3.5-fold, P = 0.015), and after 1 hour of electrical stimulation (~3.5-fold, P = 0.015). There were no significant differences in the VEGF mRNA levels between exercised and electrically stimulated muscles.

Bottom Line: A greater upregulation in oxidative regions was hypothesized.These regional differences were not significantly different from control muscle (non-exercised, non-stimulated, N = 2 muscles), although nearly so for electrically stimulated muscle (P = 0.056).However, it is not possible to determine if the VEGF mRNA signal difference is important in either the maintenance of regional capillarity differences or exercise induced angiogenesis.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Physiology, School of Medicine, University of California, San Diego 92093-0623A, USA. tbrutsae@csc.albany.edu

ABSTRACT

Background: Vascular endothelial growth factor (VEGF) mRNA levels increase in rat skeletal muscle after a single bout of acute exercise. We assessed regional differences in VEGF165 mRNA levels in rat gastrocnemius muscle using in situ hybridization after inducing upregulation of VEGF by treadmill running (1 hr) or electrical stimulation (1 hr). Muscle functional regions were defined as oxidative (primarily oxidative fibers, I and IIa), or glycolytic (entirely IIb or IId/x fibers). Functional regions were visualized on muscle cross sections that were matched in series to slides processed through in situ hybridization with a VEGF165 probe. A greater upregulation in oxidative regions was hypothesized.

Results: Total muscle VEGF mRNA (via Northern blot) was upregulated 3.5-fold with both exercise and with electrical stimulation (P = 0.015). Quantitative densitometry of the VEGF mRNA signal via in situ hybridization reveals significant regional differences (P

Conclusions: Moderately higher VEGF mRNA signal in oxidative muscle regions is consistent with regional differences in capillary density. However, it is not possible to determine if the VEGF mRNA signal difference is important in either the maintenance of regional capillarity differences or exercise induced angiogenesis.

Show MeSH
Related in: MedlinePlus