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Biocompatibility of genipin and glutaraldehyde cross-linked chitosan materials in the anterior chamber of the eye.

Lai JY - Int J Mol Sci (2012)

Bottom Line: The interleukin-6 expressions at mRNA level were also detected by quantitative real-time reverse transcription polymerase chain reaction.As compared to the non-cross-linked counterparts, the GP-chi samples improved the preservation of corneal endothelial cell density and possessed better anti-inflammatory activities, indicating the benefit action of the GP cross-linker.In summary, the intracameral tissue response to the chemically modified chitosan materials strongly depends on the selection of cross-linking agents.

View Article: PubMed Central - PubMed

Affiliation: Institute of Biochemical and Biomedical Engineering, Chang Gung University, Taoyuan 33302, Taiwan; E-Mail: jylai@mail.cgu.edu.tw ; Tel.: +886-3-211-8800 (ext. 3598); ; Biomedical Engineering Research Center, Chang Gung University, Taoyuan 33302, Taiwan ; Molecular Medicine Research Center, Chang Gung University, Taoyuan 33302, Taiwan.

ABSTRACT
Chitosan is a naturally occurring cationic polysaccharide and has attracted much attention in the past decade as an important ophthalmic biomaterial. We recently demonstrated that the genipin (GP) cross-linked chitosan is compatible with human retinal pigment epithelial cells. The present work aims to further investigate the in vivo biocompatibility of GP-treated chitosan (GP-chi group) by adopting the anterior chamber of a rabbit eye model. The glutaraldehyde (GTA) cross-linked samples (GTA-chi group) were used for comparison. The 7-mm-diameter membrane implants made from either non-cross-linked chitosan or chemically modified materials with a cross-linking degree of around 80% were inserted in the ocular anterior chamber for 24 weeks and characterized by slit-lamp and specular microscopic examinations, intraocular pressure measurements, and corneal thickness measurements. The interleukin-6 expressions at mRNA level were also detected by quantitative real-time reverse transcription polymerase chain reaction. Results of clinical observations showed that the overall ocular scores in the GTA-chi groups were relatively high. In contrast, the rabbits bearing GP-chi implants in the anterior chamber of the eye exhibited no signs of ocular inflammation. As compared to the non-cross-linked counterparts, the GP-chi samples improved the preservation of corneal endothelial cell density and possessed better anti-inflammatory activities, indicating the benefit action of the GP cross-linker. In summary, the intracameral tissue response to the chemically modified chitosan materials strongly depends on the selection of cross-linking agents.

No MeSH data available.


Related in: MedlinePlus

Representative slit-lamp biomicroscopic images of rabbit eyes 24 weeks after surgical insertion of various chitosan implants in the ocular anterior chamber. (A) Ctrl (sham-operated); (B) Chi; (C) GTA-chi; and (D) GP-chi groups. Scale bars: 3 mm.
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f1-ijms-13-10970: Representative slit-lamp biomicroscopic images of rabbit eyes 24 weeks after surgical insertion of various chitosan implants in the ocular anterior chamber. (A) Ctrl (sham-operated); (B) Chi; (C) GTA-chi; and (D) GP-chi groups. Scale bars: 3 mm.

Mentions: Figure 1 shows representative slit-lamp biomicroscopic images for each group. After surgery for 24 weeks, the cornea in the sham-operated rabbits (received no implant) was clear. Additionally, the anterior chamber was quiet (no cells or flare). In the Chi groups, the 7-mm-diameter membranes were still visible at the graft site. However, the structural integrity of the implants was deteriorated since significant loss of non-cross-linked chitosan materials might have occurred during a 24-week in vivo degradation. The rabbit eyes showed very mild inflammation in the anterior chamber. After intraocular implantation of GTA-chi samples, severe ocular tissue responses, including aqueous flare, anterior chamber fibrin, corneal cloudiness, corneal neovascularization, iris neovascularization, and lens opacity were observed. By contrast, in the GP-chi groups, the implants appeared dark blue in color, mainly due to the formation of dark blue pigments via the reaction of GP with chitosan. These membranes remained stable in all rabbits at 24 weeks following surgery and demonstrated a slight reduction in size by 5%–10%. Of note, the eyes bearing the GP cross-linked materials showed no evidence of ocular inflammation.


Biocompatibility of genipin and glutaraldehyde cross-linked chitosan materials in the anterior chamber of the eye.

Lai JY - Int J Mol Sci (2012)

Representative slit-lamp biomicroscopic images of rabbit eyes 24 weeks after surgical insertion of various chitosan implants in the ocular anterior chamber. (A) Ctrl (sham-operated); (B) Chi; (C) GTA-chi; and (D) GP-chi groups. Scale bars: 3 mm.
© Copyright Policy - open-access
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC3472724&req=5

f1-ijms-13-10970: Representative slit-lamp biomicroscopic images of rabbit eyes 24 weeks after surgical insertion of various chitosan implants in the ocular anterior chamber. (A) Ctrl (sham-operated); (B) Chi; (C) GTA-chi; and (D) GP-chi groups. Scale bars: 3 mm.
Mentions: Figure 1 shows representative slit-lamp biomicroscopic images for each group. After surgery for 24 weeks, the cornea in the sham-operated rabbits (received no implant) was clear. Additionally, the anterior chamber was quiet (no cells or flare). In the Chi groups, the 7-mm-diameter membranes were still visible at the graft site. However, the structural integrity of the implants was deteriorated since significant loss of non-cross-linked chitosan materials might have occurred during a 24-week in vivo degradation. The rabbit eyes showed very mild inflammation in the anterior chamber. After intraocular implantation of GTA-chi samples, severe ocular tissue responses, including aqueous flare, anterior chamber fibrin, corneal cloudiness, corneal neovascularization, iris neovascularization, and lens opacity were observed. By contrast, in the GP-chi groups, the implants appeared dark blue in color, mainly due to the formation of dark blue pigments via the reaction of GP with chitosan. These membranes remained stable in all rabbits at 24 weeks following surgery and demonstrated a slight reduction in size by 5%–10%. Of note, the eyes bearing the GP cross-linked materials showed no evidence of ocular inflammation.

Bottom Line: The interleukin-6 expressions at mRNA level were also detected by quantitative real-time reverse transcription polymerase chain reaction.As compared to the non-cross-linked counterparts, the GP-chi samples improved the preservation of corneal endothelial cell density and possessed better anti-inflammatory activities, indicating the benefit action of the GP cross-linker.In summary, the intracameral tissue response to the chemically modified chitosan materials strongly depends on the selection of cross-linking agents.

View Article: PubMed Central - PubMed

Affiliation: Institute of Biochemical and Biomedical Engineering, Chang Gung University, Taoyuan 33302, Taiwan; E-Mail: jylai@mail.cgu.edu.tw ; Tel.: +886-3-211-8800 (ext. 3598); ; Biomedical Engineering Research Center, Chang Gung University, Taoyuan 33302, Taiwan ; Molecular Medicine Research Center, Chang Gung University, Taoyuan 33302, Taiwan.

ABSTRACT
Chitosan is a naturally occurring cationic polysaccharide and has attracted much attention in the past decade as an important ophthalmic biomaterial. We recently demonstrated that the genipin (GP) cross-linked chitosan is compatible with human retinal pigment epithelial cells. The present work aims to further investigate the in vivo biocompatibility of GP-treated chitosan (GP-chi group) by adopting the anterior chamber of a rabbit eye model. The glutaraldehyde (GTA) cross-linked samples (GTA-chi group) were used for comparison. The 7-mm-diameter membrane implants made from either non-cross-linked chitosan or chemically modified materials with a cross-linking degree of around 80% were inserted in the ocular anterior chamber for 24 weeks and characterized by slit-lamp and specular microscopic examinations, intraocular pressure measurements, and corneal thickness measurements. The interleukin-6 expressions at mRNA level were also detected by quantitative real-time reverse transcription polymerase chain reaction. Results of clinical observations showed that the overall ocular scores in the GTA-chi groups were relatively high. In contrast, the rabbits bearing GP-chi implants in the anterior chamber of the eye exhibited no signs of ocular inflammation. As compared to the non-cross-linked counterparts, the GP-chi samples improved the preservation of corneal endothelial cell density and possessed better anti-inflammatory activities, indicating the benefit action of the GP cross-linker. In summary, the intracameral tissue response to the chemically modified chitosan materials strongly depends on the selection of cross-linking agents.

No MeSH data available.


Related in: MedlinePlus