Intervertebral disc needle puncture injury can be repaired using a gelatin–poly (γ-glutamic acid) hydrogel: an in vitro bovine biomechanical validation
The subtle impairments of the disc due to anular punctures may have an immediate effect on the functional integrity due to the altered intradiscal pressure, hence the subsequent catabolic degradation. This study evaluates functional restoration of needle puncture injured intervertebral discs with a newly developed injectable hydrogel using the quantitative discomanometry (QD) test. The proposed hydrogel is composed of gelatin and poly (γ-glutamic acid) (γ-PGA) and crosslinked with 1-(3-dimethylaminopropyl)-3-ethyl-carbodiimide hydrochloride (EDC).
Thirty-six bovine motion segments were distributed into six groups. Needle puncture injured discs were created in all discs except for those in the first group (intact). The second group included injured discs that received no treatment (injury). The remaining four groups included injured discs repaired with injected hydrogels fabricated with different polymer solutions and EDC concentrations including: gelatin/γ-PGA solution crosslinked with the EDC solution at a 10:1 and 40:1 ratio to form the GP/E(10:1) and GP/E(40:1) groups, respectively, and gelatin and γ-PGA solution crosslinked with the EDC solution at a 10:1 ratio to form the G/E(10:1) or P/E(10:1) groups. The QD tests were performed to evaluate disc integrity of all six groups.
Among all hydrogel repair groups, the GP/E(10:1) group was found to have the highest leakage and saturate pressure and was the only group comparable to the intact one.
Restoration of disc integrity secondary to needle puncture injury can be achieved via the repair with the newly developed gelatin hydrogel incorporated with γ-PGA and EDC.
KeywordsAnulus fibrosus repair Filling sealant Gelatin–poly (γ-glutamic acid) injectable hydrogel Intradiscal pressure Quantitative discomanometry
This study was supported by Ministry of Science and Technology, Taiwan (MOST 104-2221-E-002-121-MY3, MOST 104-2221-E-002-212-MY3, MOST 104-2314-B-016-001).
Compliance with ethical standards
Conflict of interest
The authors report no confict of interest concerning the materials or methods used in this study or the finding specified in this paper.
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