Storage-associated artefact in equine muscle biopsy samples.

This research scrutinizes how the severity of storage-induced artifacts in horse muscle samples is impacted by alterations in temperature, storage duration, and hydration status. The study advocates careful shipment of these samples in dry gauze, sealed in plastic, and transported on ice packs within 24 hours to minimize artifacts.

Objective and Methodology

• The central goal of this research was to understand how storage conditions, specifically varying temperature, storage time and hydration levels could affect the quality of equine muscle tissue biopsy samples. These factors are observed to influence the occurrence of storage-induced artifacts, which can potentially compromise the histological interpretation of the samples.
• The experiment consisted of obtaining skeletal muscle samples from 8 horses immediately post euthanasia. Six independent samples were taken from each horse. While one sample was frozen immediately using isopentane precooled in liquid nitrogen, the rest were stored under different conditions to replicate possible situations encountered in practice.
• After storage, these samples were again frozen under similar conditions and subsequently stained using haematoxylin and eosin. They were then evaluated for artifacts by two different blinded observers.
• The best quality samples were further processed with a range of routine stains and marked for collagen V to facilitate measurement of minimum fiber diameters.

Results

• The main findings of the study highlight that prolonged storage and increased hydration led to more storage-associated artifacts in the muscle samples. Samples stored for 24 hours in dry gauze at low temperature were found to be better in quality as compared to those placed on damp gauze.
• Notably, the study also found the histochemical staining techniques typically used in practice were not impacted by 24 hours of chilled storage.
• Interestingly, the average fiber diameter was not significantly affected by storage. However, storage in either dry or damp conditions for 24 hours did increase the variability in fiber sizes significantly. This suggests a shift in the distribution of fiber sizes rather than a generalized change being induced due to storage.

Conclusions

• Care needs to be exercised when interpreting fiber size profiles in shipped samples. It is possible that storage-associated artifacts might affect our understanding of these attributes.
• The research suggests that equine muscle biopsy samples are ideally shipped in dry gauze, sealed in plastic containers, and transported on ice packs. If these conditions are maintained so that the samples can be processed within 24 hours, the likelihood of encountering storage-induced artifacts can be minimized. This, in turn, enables the receiving laboratory to interpret the samples with minimal artifacts.