Human muscle gene expression following resistance exercise and blood flow restriction

Abstract

Introduction: Blood flow restriction in combination with low-intensity resistance exercise (REFR) increases skeletal muscle size to a similar extent as compared with traditional high-intensity resistance exercise training. However, there are limited data describing the molecular adaptations that occur after REFR.

Purpose: To determine whether hypoxia inducible factor-1 alpha (HIF-1alpha) and REDD1 mRNA are expressed differently in REFR compared with low-intensity resistance exercise with no blood flow restriction (CONTROL). Secondly, to determine whether low-intensity resistance exercise is able to induce changes in mRNA expression of several anabolic and catabolic genes as typically seen with high-intensity resistance exercise.

Methods: Six subjects were studied at baseline and 3 h after a bout of leg resistance exercise (20% 1RM) in REFR and CONTROL subjects. Each subject participated in both groups, with 3 wk separating each visit. Muscle biopsy samples were analyzed for mRNA expression, using qRT-PCR.

Result: Our primary finding was that there were no differences between CONTROL and REFR for any of the selected genes at 3 h after exercise (P > 0.05). However, low-intensity resistance exercise increased HIF-1alpha, p21, MyoD, and muscle RING finger 1 (MuRF1) mRNA expression and decreased REDD1 and myostatin mRNA expression in both groups (P < 0.05).

Conclusion: Low-intensity resistance exercise can alter skeletal muscle mRNA expression of several genes associated with muscle growth and remodeling, such as REDD1, HIF-1alpha, MyoD, MuRF1, and myostatin. Further, the results from REFR and CONTROL were similar, indicating that the changes in early postexercise gene expression were attributable to the low-intensity resistance exercise bout, and not blood flow restriction.

Conflict of interest statement

The authors report no conflict of interest or endorsement by ACSM.

Figures

Figure 1

Results represent A) HIF-1α and B) REDD1 mRNA expression between CONTROL and REFR at baseline and 3h post resistance exercise. Values are mean ± SEM. * indicates main effect for time when CONTROL and REFR are combined (P

Figure 2

Results represent A) p21 and B) Cyclin D1 mRNA expression between CONTROL and REFR at baseline and 3h post resistance exercise. Values are mean ± SEM. * indicates main effect for time when CONTROL and REFR are combined (P

Figure 3

Results represent A) IGF-1 and B) MGF mRNA expression between CONTROL and REFR at baseline and 3h post resistance exercise. Values are mean ± SEM.

Figure 4

Results represent A) MyoD and B) Myogenin mRNA expression between CONTROL and REFR at baseline and 3h post resistance exercise. Values are mean ± SEM. * indicates main effect for time when CONTROL and REFR are combined (P

Figure 5

Results represent Myostatin mRNA expression between CONTROL and REFR at baseline and 3h post resistance exercise. Values are mean ± SEM. * indicates main effect for time when CONTROL and REFR are combined (P

Figure 6

Results represent A) mTOR and B) S6K1 mRNA expression between CONTROL and REFR at baseline and 3h post resistance exercise. Values are mean ± SEM.

Figure 7

Results represent A) MuRF1 and B) MAFbx mRNA expression between CONTROL and REFR at baseline and 3h post resistance exercise. Values are mean ± SEM. * indicates main effect for time when CONTROL and REFR are combined (P