Assessment of Exogenous Cross-Linking Therapy for Intervertebral Disc Degeneration - An ex vivo Study Using Whole Disc Culture System
Date Issued
2011
Date
2011
Author(s)
Chang, Ya-Ching
Abstract
Objective: To investigate the efficacy of exogenous cross-linking therapy in treating the degenerated intervertebral disc by using ex vivo whole disc culture system.
Summary of background data: Disc degeneration induced low back pain syndrome is observed in elderly human. The disc degeneration can be induced by factors such as protein denaturation and micro-defect within disc fiber. A disc degeneration model can be effectively used for the screening of clinical strategy for disc degeneration treatment. The treatment based on this model can be studied to find the physiological effect. In recent studies, exogenous cross-linking therapy has been shown to enhance stability and dynamic properties of disc by increasing protein cross-linking. Nevertheless, the mechanical and biological effects of peptide cross-linking reagent on different degrees of disc degeneration shall be concerned to further assess the feasibility of exogenous cross-linking therapy.
Methods: Total 40 porcine thoracic discs (T1~T6) were dissected from 6-month-old juvenile pigs within 4 hours after sacrifice. After specimen preparation, discs were equally assigned to five groups (n=8 for each group), and all specimens were incubated for 1 week before test. Groups were divided as follows: intact group, early degenerated group, early degenerated with treatment group, severely degenerated group, severely degenerated with treatment group. For all groups except intact group, 0.5 ml 0.25% trypsin solution was injected into specimen on Day 1 to produce protein denaturation, which is the simulation for early degenerated disc, and high strength fatigue loading (Frms= 420 N, frequency= 2.5 Hz, loading period= 4 hours) was given to produce micro-defects within disc fiber to resembling the severe disc degeneration on Day 2. For groups with treatment, specimens were injected with 1 ml 0.33% genipin solution after simulation of disc degeneration. Mechanical test and biological detection were performed after one week incubation.
Result: In group of early degenerated disc, the results showed that the mechanical property of disc significantly decreased both in static and dynamic test, and also the disorganization of the laminate structure was found in histological stain. If the disc is damaged by fatigue loading after protein denaturation, the aggregate modulus and stiffness increase with height loss, but damping coefficient, permeability and water content decrease because of structural defects. This defect was also found in histological stain. After taking exogenous cross-linking therapy, the degenerated disc recover its mechanical property and restores the water content to normal condition, but the structural defects which occur in severely degenerated disc cannot be repair by cross-linker.
Conclusion: Genipin-treated discs show the recovery of mechanical properties after protein denaturation which presumes to be process of early disc degeneration, and the efficacy maintains for at least one week; however, mechanical defects which occur in severely degenerated disc cannot be treated by protein cross-linking.
Subjects
intervertebral disc
degeneration model
exogenous cross-linking
genipin
ex vivo whole disc culture system
Type
thesis
File(s)![Thumbnail Image]()
Loading...
Name
ntu-100-R98548018-1.pdf
Size
23.54 KB
Format
Adobe PDF
Checksum
(MD5):32d59afabc8b52b5ace3e2c2160b846c