Related Experiment Videos
Viability of hypothermic preserved muscle determined by gene expression levels
1Department of Orthopaedic Surgery, Nara Medical University, Nara, Japan.
Abstract:
We report a muscle viability index (MVI) that reflects mRNA degradation. The viability of hypothermically preserved (48C) rat skeletal muscle was evaluated using this MVI. To evaluate the hypothermic ischaemic insult of the muscle, 21 hind limbs of Fischer rats (three subgroups of seven limbs each) were hypothermically preserved for 1h, 3h and 6h, before harvesting the tibialis anterior muscle. To investigate reperfusion injury after hypothermic preservation, an additional 28 limbs were transplanted to recipient Fischer rats after hypothermic ischaemia for either 3h or 6h. The transplanted muscles were harvested on either day 3 or day 7 after transplantation. Seven fresh muscles were also harvested, and used as controls. In the 3h ischaemia group, the MVIs of both the hypothermic-ischaemia and the ischaemia-reperfusion subgroups were comparable to the controls. Likewise, there were no significant differences between the controls and the 6h hypothermic ischaemia and ischaemia-reperfusion subgroups. These results show that muscle viability is maintained with hypothermic preservation of up to 6h, and after reperfusion. Therefore, in clinical replantations the amputated extremity should be preserved under hypothermic conditions from the time of injury to the time of surgery.
Insights
Hypothermic preservation up to 6 hours maintains skeletal muscle viability, even after reperfusion. This finding supports cooling extremities from injury to surgery for clinical replantations.
Area of Science:
- Biomedical Engineering
- Surgical Research
- Muscle Physiology
Background:
- Hypothermic preservation is crucial for preserving tissue viability during ischemia.
- Assessing muscle viability after preservation and reperfusion is critical for successful replantation surgery.
Purpose of the Study:
- To introduce a novel muscle viability index (MVI) based on mRNA degradation.
- To evaluate the viability of rat skeletal muscle preserved hypothermically for up to 6 hours.
- To investigate potential reperfusion injury following hypothermic preservation.
Main Methods:
- Developed and utilized a muscle viability index (MVI) reflecting mRNA degradation.
- Hypothermically preserved rat hind limbs (4°C) for 1, 3, and 6 hours.
- Assessed muscle viability in transplanted limbs after 3 or 6 hours of ischemia and subsequent reperfusion (days 3 and 7).
Main Results:
- Muscle viability, assessed by MVI, remained comparable to controls after 3 hours of hypothermic ischemia and reperfusion.
- No significant differences in muscle viability were observed between controls and muscles subjected to 6 hours of hypothermic ischemia and reperfusion.
- The study demonstrates that muscle viability is maintained for up to 6 hours of hypothermic preservation and subsequent reperfusion.
Conclusions:
- Hypothermic preservation of skeletal muscle for up to 6 hours is safe and preserves viability.
- Reperfusion following 6-hour hypothermic preservation does not significantly compromise muscle viability.
- Clinical recommendations: preserve amputated extremities under hypothermic conditions from injury to surgical repair to maximize viability.