Development of artificial eardrums using water-soluble chitosan and tissue engineering techniques

BACKGROUND AND OBJECTIVES: Nowadays several materials like hyaluronic acid, pentoxifylline, EGF, bFGF, AlloDerm are applied to treatment of ear drum perforation. Paper patch is the most widely used material but it is not resorbable and myringoplasty needs relatively complex procedures than usual OPD based treatment. So, we developed new scaffold using watersoluble chitosan and tissue engineering techniques to improve the healing process of perforated eardrums. MATERIALS AND METHOD: Chitin is a kind of mucopolysacchride which is obtained from β-1,4 binding to N-acetylglucosamine. The scaffold was made from chitosan (poly-β-(1->4)-D-glucosamine) which derived from alkaline deacetylation of chitin. After dissolving chitosan to acetic acid, glycerol was mixed and dried in petri dish under 45 degrees centigrade. The thickness of scaffold was approximately 40μm. Tensile strength and elongation at rupture point of scaffold were obtained by texture analyzer (Stable Micro Systems Ltd., London, England). 18 Sprague-Dawley rats (4weeks, 250-300g) were anesthetized by chloralhydrate (1g/ml, 10%dilution) and bilateral anterior half of drums were perforated by micropick under surgical microscope. Chitosan patches were applied to all right side drums and all left side drums were left for spontaneous healing as a control group. To examine the healing process in regular period, all rats were anesthetized at days 7, 14, 21 and 28. The rats which showed complete healing on both sides were killed and bullas were obtained to examine the cross sectional images of healed drums in transmission electron microscopes and optical microscopes. RESULTS: Tensile strength of scaffolds was ranged from 3.21MPa to 69.23MPa and the percent of elongation was in the range of 0.54-100.93%. According to stress-strain diagram, optimal concentrations of glycerol and chitosan were 3%, respectively. The mean healing periods were 11.5 days(±7.8) in the chitosan group and 13.5 days(±7.6) in the control group, respectively(p=0.442). Healing rates on 1 week, 2 weeks, 3 weeks, and 4 weeks were 67%(12/18), 72%(13/18), 83%(15/18) and 94%(17/18) in chitosan group, and 44%(8/18), 61%(11/18), 77%(14/18) and 94%(17/18) in control group, respectively. However there was no statistically significant difference between them (1 week p=0.180; 2 weeks p=0.480; 3 weeks p=0.674, 4 weeks p=1.000). TEM findings in the chitisan group showed the lamina propria layer was regenerated with more dense fibers than in the control group and the proportion of outer radial fiber layer was higher than in the control. Cross-sectional findings of H&E stain showed more regular surface in the chitosan group than control group. CONCLUSION: These results indicate water-soluble chitosan patches could be a reliable material for the healing of tympanic membrane perforation and could provide a representative data for following studies.

Author dc:creator

• 박, 정섭

Contributors dc:contributor

• 정, 연훈
• 대학원 의학과
• 105212

• Chitosan
• 수용성 키토산
• 인조고막

Language dc:language

ko

Identifier

http://dcoll.ajou.ac.kr:9080/dcollection/jsp/common/DcLoOrgPer.jsp?sItemId=000000009195
000000009195

OAI identifier oai:identifier

oai:repository.ajou.ac.kr:201003/1805