Abstract
Introduction: The intervertebral disc is a significant contributor to back pain, and is thus a tissue that is often examined postmortem. Tissue preservation during storage is of importance both experimentally, for research and teaching purposes, and clinically, for possible use in transplantation. The biomechanical function of the disc after storage has been investigated. However, to our knowledge the biological and metabolic consequences of storage have not been studied. Here we have investigated the effects of storage in the intervertebral disc on glucose, lactate, and cell viability.
Method: A total of 53 discs from 14 bovine tails were obtained within 24 hours of slaughter. Discs were either removed immediately and wrapped in clingfilm or kept in situ, surrounded by muscle. Tissue was stored at 4_C, and samples were taken at 2 hours to 9 days. Disc tissue was analysed for lactate, glucose, and cell viability. Muscle was analysed for lactate. Statistical analysis of data was performed using Student’s t test.
Results: Lactate concentrations in discs stored in tails increased with time of storage, being significantly higher even after 24 hours (p< 0.01). In contrast, lactate levels in isolated discs remained constant. Glucose levels were undetectable in discs, irrespective of storage. Muscle lactate was always significantly higher than disc (p< 0.01). The percentage of live cells fell significantly with storage in situ (p< 0.01).
Discussion: The increase in lactate observed in discs remaining in situ appears to arise from lactate diffusing in from surrounding muscle, as no increase was noted in isolated discs. As would be expected, this high concentration of lactate and low glucose appears to affect cell viability adversely, possibly as a consequence of lowered pH. This change in metabolite concentration and hence cell viability is important to note when considering human postmortem tissue, as it may affect the biological function of the disc.
The abstracts were prepared by Dr P Dolan. Correspondence should be addressed to him at the British Orthopaedic Association, Royal College of Surgeons, 35-43 Lincoln’s Inn Fields, London WC2A 3PN.
