Effects of stretch-shortening cycle-induced muscle injury on gene expression

Details

• Personal Author:
  Baker BA ; Cutlip, Robert G. ; Geronilla KB ; Kashon M ; Metheny R ; Miller, G. Roger ; Rao KMK
• Description:
  Investigation of gene expression due to contraction-induced injury would be beneficial in elucidating the mechanisms involved in skeletal muscle response and repair. PURPOSE: To investigate the effect of stretch-shortening cycle ROM (range of motion) on gene expression in rats. METHODS: Testing was performed on dorsiflexor muscles of Sprague-Dawley rats in vivo. Animals were randomly assigned to a long ROM group (L-Inj), short ROM group (S-Inj), or isometric control group (CON). The injury protocol consisted of 7 sets of 10 S-S cycles at 500 degrees/s. The S-Inj group received S-S cycles between 70 degrees-120 degrees, whereas the L-Inj group received S-S cycles between 90 degrees-140 degrees ankle angle. The CON group received muscle stimulation only at 90 degrees. Dorsiflexor muscles were stimulated for 2.8 s each set, and sets were administered at 1-min intervals. Rats were sacrificed at 6 and 48 hours postinjury. Following sacrifice, tissue was excised, weighed, sectioned, quick-frozen, and stored at -80 degrees C. Tissue samples were homogenized directly in Lysis buffer, quick-frozen, and stored at -80 degrees C until RNA isolation. RNA was isolated, followed by reverse transcription (RT) and polymerase chain reaction (PCR). Changes in the expression (mRNA) of several genes of interest were measured by real-time PCR. RESULTS: No significant differences were found with respect to collagen-III, IL-1[beta], neonatal myosin, desmin, or IGF-1, whereas significant differences were found with MGF (muscle growth factor). MGF displayed a significant treatment-time interaction (p < 0.05). Post-hoc analysis indicated S-Inj at 48 hr was greater than CON at 48 hr (p < 0.05). Also, the S-Inj at 48 h was greater than the S-Inj at 6 hr (p < 0.05). Furthermore, the L-Inj at 6 hr was greater than S-Inj at 6 hr (p < 0.05). CON at 6 hr was greater than CON at 48 hr (p < 0.05). CONCLUSION: Stretch-shortening cycles increased gene expression of MGF but not IGF-1 in this model over time, and also resulted in elevated levels as compared to isometrically exercised controls. MGF is thought to have an autocrine function while IGF-1 has a systemic function. [Description provided by NIOSH]
• Subjects:
  Animals Genetics Laboratories Musculoskeletal Diseases Musculoskeletal System Occupational Health Safety
• Keywords:
  Genes Injuries Laboratory-animals Mechanical-properties Muscle-contraction Muscle-function Muscle-stress Muscle-tension Muscle-tissue Muscles Musculoskeletal-system Musculoskeletal-system-disorders

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• ISSN:
  0195-9131
• Document Type:
  Text
• Genre:
  Abstract or Summary
• Place as Subject:
  OSHA Region 3 ; West Virginia
• CIO:
  National Institute for Occupational Safety and Health (NIOSH)
• Division:
  HELD - Health Effects Laboratory Division
• Topic:
  Workplace Safety & Health
• Location:
  North America
• Volume:
  35
• Issue:
  5
• NIOSHTIC Number:
  nn:20044069
• Citation:
  Med Sci Sports Exerc 2003 May; 35(5)(Suppl 1):S157
• Federal Fiscal Year:
  2003
• Peer Reviewed:
  False
• Source Full Name:
  Medicine and Science in Sports and Exercise
• Supplement:
  1
• Collection(s):
  National Institute for Occupational Safety and Health
• Main Document Checksum:
  urn:sha-512:e3d7160930f3e6753372d02ed32d93b9c7073920bf61c55e705c18ec2608039a7adfdb86600331d2027fbe1d64c6c8f396960f216e452fc44d39579102d2e4a6
• Download URL:
  https://stacks.cdc.gov/view/cdc/199919/cdc_199919_DS1.pdf
• File Type:
  [PDF - 38.54 KB ]