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Chemonucleolysis with calpain I in rabbits
S Wakita1, K Shimizu, K Suzuki
1Department of Orthopaedic Surgery, Faculty of Medicine, Kyoto University, Japan.
Spine
|January 1, 1993
Summary
Calpain I, a calcium-dependent enzyme, degrades disc proteoglycans, causing temporary changes in rabbit intervertebral discs. Recovery was observed after eight weeks, suggesting potential clinical applications.
Area of Science:
- Biochemistry
- Cell Biology
- Orthopedics
Background:
- Calpain I is a calcium-dependent cysteine proteinase.
- It has been shown to degrade proteoglycan in vitro.
- Proteoglycan degradation is implicated in intervertebral disc degeneration.
Purpose of the Study:
- To investigate the effects of injecting purified calpain I into rabbit intervertebral discs.
- To assess the potential of calpain I as a chemonucleolytic agent for disc treatment.
Main Methods:
- Calpain I was purified from human red blood cells and injected into rabbit intervertebral discs.
- Disc space narrowing was assessed via roentgenograms.
- Histological analysis examined proteoglycan content and cell viability.
- Biochemical analysis quantified proteoglycan changes in the nucleus pulposus.
Main Results:
- Injected calpain I caused disc space narrowing and decreased proteoglycan in nucleus pulposus and anulus fibrosus.
- Notochordal cells in the nucleus pulposus significantly decreased.
- Biochemical analysis revealed an increase in smaller proteoglycans.
- Histological and biochemical recovery was observed by eight weeks post-injection.
Conclusions:
- Calpain I is a potent enzyme for proteoglycan degradation, comparable to chondroitinase ABC but with milder action than chymopapain.
- Autogenous calpain I may offer an advantage by preventing anaphylactic reactions.
- Further research into calpain I's clinical application for disc disorders is warranted.