Inhibition of Satellite Cells Proliferation with AraC Prolonged Survival of Adult Skeletal Muscle Fiber in Culture
Bibliographic record
Abstract
The skeletal muscle is a dynamic tissue that has the ability to change and modify itself to fit the level of required activity; a phenomenon called muscle plasticity. Most studies of muscle plasticity are carried out in situ, a condition for which it is difficult to study and discern between the intrinsic properties of skeletal muscle, the myokines released by muscle fibers and the neurotrophic factors released by neurons innervating skeletal muscles that play various roles in the mechanisms of muscle plasticity. Another approach is to study the morphological and behavior of single adult muscle fibers under culture conditions for which one can fully control the level of activity and exogenous factors affecting muscle plasticity. However, single muscle fiber survival has been shown to be limited to a few days. The objective of this study was to optimize fiber survival in culture. Mouse FDB fibers were separated by trituration following a 3 hrs collagenase treatment at 37°C. When tested the day of the preparation, FDB fibers have normal morphology, normal resting membrane potential and calcium release during contraction. However, when maintained in culture at 37°C, they either degenerated or supercontracted and intact fibers are basically depleted within 5–7 days. Satellite cells are known to proliferate when fibers are maintained in culture and we tested whether an inhibition of their proliferation improves fiber survival. Exposing fibers under resting conditions to 50 μM AraC, a mitotic inhibitor, significantly improved fiber survival by significantly reducing the number of degenerating fibers. We also determined that i) MEM is a better medium than DMEM; ii) changing 50% of the culture medium every two days improved fiber survival compared to changing the medium every day; and iii) a collagen/laminin mixture as adhering substrate to improve fiber adhesion to glass coverslip gave rise to a better fiber survival than Matrigel. Together, the use of AraC, MEM, collagen/laminin and changing medium every two days resulted in having more than 60% of the fibers maintaining normal morphology up to 18 days. A large loss of fibers was then observed over the next 3 days primarily because of supercontraction. The results suggest i) that when satellite cells are allowed to proliferate they may contribute to the degeneration of fibers under resting conditions and ii) that the release of myokines by skeletal muscle fibers likely play a role in fiber survival (as removing 50% of medium every day lowered fiber survival). Support or Funding Information The study was supported by the National Science and Engineering Research Council of Canada (NSERC)
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.001 |
| Insufficient payload (model declined to judge) | 0.001 | 0.001 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".