Biological roles of carboxymethyl‐chitin associated for the growth factor production

Abstract

Many techniques to restore cartilage defection have been tried. However, the development is still under way because of problems, including loosening of artificial joint, degenerative change of compensated tissue, risk of viral transmission via allograft/autograft, and cost of therapeutic materials for repair. In the previous research, we found that complementing cartilage defective part with carboxymethyl-chitin (CM-chitin)/beta-tricalcium phosphate composite induced regeneration of cartilage in rabbits in vivo, and it is presumable that CM-chitin plays a key role in chondrogenesis causing the regeneration of cartilage. However, the induction mechanism of chondrogenesis with CM-chitin is still unclear. In this study, we investigated the cell responses to CM-chitin by using peritoneal exudate cell (PEC) in mice and found that CM-chitin induced the expression of inflammatory cytokines and growth factors, both of which are both considered to correlate with chondrogenesis. After intraperitoneal injection CM-chitin showed enhanced expressions of mRNA of interleukin-1beta (IL-1beta), interleukin-6 (IL-6), keratinocyte-derived chemokine, tumor necrosis factor-alpha, and transforming growth factor-beta1 (TGF-beta1) in PEC as observed by reverse transcriptase polymerase chain reaction. Productions of TGF-beta1 protein were confirmed by enzyme linked immunosorbant assay. It was also shown that mononuclear cells in PEC were responsible for the TGF-beta1 production. These results suggest that CM-chitin is an inductor of inflammatory cytokines and growth factors and may contribute to regeneration of cartilage.

Influence of carboxymethyl chitin on stability and biocompatibility of 3D nanohydroxyapatite/gelatin/carboxymethyl chitin composite for bone tissue engineering

“…17 It is also accounted in cartilage restoration by induction of inflammatory cytokine and growth factors. 18 The intravascular resorbability of carboxymethyl chitin considers it efficient in terms of biological safety which is due to its hydrolysis to an oligomer during inflammation followed by its excretion as urea. [19][20][21][22][23][24][25] Our objective was based on a biomimetic approach, in which we prepared a series of 3D scaffolds including n-HA/ gel and n-HA/gel/CMC using the solvent-casting method combined with freeze-drying and compared them, so as to test the effect of CMC (prepared by chemical modification of chitin) on the developed construct.…”

Carboxymethyl‐chitin promotes chondrogenesis by inducing the production of growth factors from immune cells

“…The LDH values and cell numbers of each group were analyzed for statistical significance using Welch's t ‐test. Total RNA was extracted from the cells at 7, 14, and 21 days, and the mRNA expression of growth factors and cartilage‐related genes was analyzed using the reverse‐transcriptase polymerase chain reaction (RT‐PCR) as described previously 23. The pairs of primer sequences used were as follows: For β‐actin: 5′‐ATGGATGACGATATCGCT‐3′ (sense) and 5′‐ATGAGGTAGTCTGTCAGGT‐3′ (antisense).…”

“…We recently found that CM‐chitin stimulates immune cells to produce TGF‐β1, a growth factor for cartilage regeneration 23. However, it was unclear whether the stimulation of cells by CM‐chitin leads to cartilage regeneration.…”

“…The regeneration of cartilage was observed after treatment with the CM‐chitin/β‐TCP composite but not with β‐TCP alone 8 weeks after implantation, indicating that CM‐chitin plays a key role in the regeneration of cartilage. Previously, we also showed that CM‐chitin stimulated murine peritoneal exudate cells (PEC) to induce the expression of inflammatory cytokines and TGF‐β1 23. TGF‐β1 has many functions,24 including the induction of mesenchymal cell condensation, which is required for in vitro chondrogenesis 25–27.…”