Summary: | 碩士 === 國立臺灣大學 === 醫學工程學研究所 === 96 === Disc degeneration is strongly associated with back pain and herniation resulting in the cost of health care decreasing. Some evidence shows that disc degeneration originates in the nucleus pulposus (NP). However, current treatments such as physical therapy, pharmaceutical treatment, spinal fusion, artificial disc replacement and discectomy attempt to reduce pain rather than repair the degenerated disc. Cell–based therapies are aimed at repairing the degenerated disc, which is a potential treatment of disc degeneration. Therefore, the purpose of this study was to prepare the thermosensitive hydrogel as cell carrier of NP cells.
In this study, the thermosensitive chitosan/gelatin/β- glycerol phosphate disodium salt hydrogels (C/G/GP hydrogels) was investigated. Nucleus pulposus cells which were harvested from the intervertebral discs of the adult New Zealand white rabbits were encapsulated in C/G/GP hydrogels. The gelation temperature, gelation time and gel strength were evaluated by rheometer. Compared with the formulations using only C/GP, the gel strength of C/G/GP was increased at 37°C. In the C/G/GP system, raising the concentration of gelatin resulted in a decrease in the gelation temperature and gelation time. The results of the in vitro cytotoxicity showed that the C/GP and the C/G/GP hydrogel are biocompatible. In the degradation test, raising the concentration of gelatin seems to increase the percentage of weight loss. The ratio of sulfated glycosaminoglycan (GAG) to DNA of NP cells cultured in hydrogels showed significantly higher than monolayer-cultured at the end of 3-week. Compared with monolayer-cultured, the mRNA expression of type II Collagen, Aggrecan, MMP-3, MMP-9, IGF-1, BMP-7 and TGF-β in hydrogel-cultured NP cells was significantly enhanced.
The results showed that the C/G/GP solution remains liquid at room temperature but form the hydrogel at approximate body temperature under a neutral pH. The formed hydrogel is biocompatible and biodegradable. As three-dimensional carrier for NP cell culture, these results suggest the C/G/GP hydrogel is a suitable scaffold for the cell culture. These features make the C/G/GP hydrogel potential application as an injectable cell carrier for NP regeneration.
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