兔角膜穿通伤愈合过程中生物力学的研究

发布时间：2018-04-13 15:33

本文选题：角膜 + 生物力学　；参考：《河北医科大学》2012年硕士论文

【摘要】：角膜是位于眼球最前部的透明组织，，占整个眼球总屈光力的70%。同时，角膜因与外界直接接触，最易受到外界损伤。研究表明，眼球外伤中角膜破裂伤占33.28%。，如果处理不当可造成严重后果，甚至失明。因此，研究角膜穿通伤对于治疗此类致盲性疾病具有重要的指导意义。研究表明，角膜内部胶原纤维的本质是各向异性的，因此角膜是一种具有各向异性的生物材料，其内部胶原纤维的排列肯定会影响角膜伤口愈合的承载能力以及角膜形状。角膜伤口愈合过程中，角膜基质细胞转化为成纤维细胞或肌成纤维细胞，以促进角膜伤口的愈合，同时因细胞特性会发生转变，细胞会丧失其透明特性，进而导致角膜瘢痕，影响视功能。目前,角膜穿通伤多采用10-0尼龙缝线间断缝合的方法。一般在术后45天至90天拆除角膜缝线。众所周知，如果过早的拆除角膜缝线，可能造成角膜伤口未完全愈合，从而降低角膜韧性；如果拆除角膜缝线过晚，不但会因角膜缝线的长时间存在给患者带来长时间的痛苦，还会因为角膜缝线的刺激，使角膜瘢痕愈合，降低角膜的透明度，加剧角膜散光，影响术后视力。因此。探讨角膜缝线最佳拆除时间是很必要的。然而，目前尚缺乏相关报道。因此，本研究旨在探索角膜最佳拆线时间，以在增强角膜韧性的同时可以减少瘢痕形成及角膜散光。第一部分兔角膜穿通伤愈合过程中生物力学的变化目的：研究缝线缝合兔角膜角膜穿通伤术后不同时间点的角膜生物力学变化方法：40只兔制作中央角膜穿通伤缝合术模型。随机分为8组，每组5只，分别于术后1周、2周、3周、4周、5周、6周、7周、8周取5个伤口处角膜条试件在BOSE electroforce3220-AT生物力学试验机上进行拉伸破坏实验。结果：随着术后时间的增长，兔角膜承受的拉力逐渐增大，到6周后逐渐稳定。前6周任意两个时间点相比较均有统计学意义(P＜0.01),6周与7周比较无明显统计学意义(P0.05)。结论：兔角膜穿通伤术后6周已达较大的抗拉力能力，是拆线的最佳时机。第二部分兔角膜穿通伤愈合过程中角膜标记物的变化目的：检测分析兔角膜穿通伤术后不同时间点角膜内keratocan、vimentin、CD90和α-SMA标记蛋白的变化。旨在观察角膜达最大拉力时角膜瘢痕形成情况。为临床角膜缝合术后最佳拆线时间提供参考。方法：32只兔制作中央角膜穿通伤模型。随机分为8组，每组4只，分别于术后1周、2周、3周、4周、5周、6周、7周、8周取完整角膜，采用RT-PCR方法检测各时间点中角膜内keratocan、vimentin、CD90、α-SMA基因的表达情况。然后，通过免疫组织化学实验测定角膜中vimentin、α-SMA蛋白的含量。结果：RT-PCR结果表明：兔角膜穿通伤缝合术后伤口愈合过程中角膜基质细胞标记物keratocan随着时间的增长其表达逐渐下降，前6周下降比较显著，6周后表达逐渐平稳。同时出现成纤维细胞和肌成纤维细胞标记物CD90和α-SMA的表达，且表达随着时间的延长逐渐增强，前6周增高比较明显，6周后表达逐渐平稳。上述蛋白各自从术后1周到6周之间两两比较均有统计学意义(P＜0.01)，6周到8周之间两两比较无明显统计学意义(P0.05)。随着术后时间的延长，vimentin的表达逐渐增多，术后1周到6周之间两两比较均有差异(P＜0.01)。6周与7周比较无明显统计学意义(P0.05)。免疫组化数据显示：随着术后观察时间的延长，肌成纤维细胞标记物α-SMA的表达量逐渐增多，且术后6周时变化最显著。与前五个时间点任意两点比较均有统计学意义(P＜0.01)。间质细胞标记物vimentin的表达呈先增多然后逐渐降低趋势，且术后3周时表达量最高。结论：兔角膜穿通伤愈合过程中角膜基质细胞逐渐减少且转化为成纤维或肌成纤维细胞。术后6周时角膜基质细胞转化趋于稳定。
[Abstract]:The cornea is the most transparent tissue of the eyeball in front of the eye, accounted for the total refractive power of the cornea 70%. at the same time, due to direct contact with the outside world, the most vulnerable to external damage. The study shows that the traumatic corneal rupture accounted for 33.28%., if improper handling can cause serious consequences, and even blindness. Therefore, the research of corneal penetrating injury an important guiding significance for the treatment of such disease causing blindness.
Research shows that the essence of internal corneal collagen fiber is anisotropic, so the cornea is an anisotropic biological material, its internal collagenous fibers will affect the bearing capability of corneal wound healing and corneal shape. The process of corneal wound healing, corneal stromal cells into fibroblasts or myofibroblasts, in order to promote corneal wound healing, at the same time because cells changed and the cells lose their transparent properties, leading to corneal scar, affect the visual function.
At present, corneal penetrating wound method using 10-0 nylon suture suture. In general, after 45 to 90 days removed corneal suture. As everyone knows, if the early removal of corneal suture may cause corneal wound not healed completely, so as to reduce the toughness of the cornea; if removed corneal suture late, will not only for a long time corneal suture the existence of patients brought long time pain, but also because the stimulation of corneal sutures to reduce corneal scar healing, corneal transparency, aggravation of corneal astigmatism, affect visual acuity. Therefore. To investigate the corneal suture the best removal time is necessary. However, there is still a lack of relevant reports.
Therefore, the aim of this study is to explore the best time for the disassembly of the cornea, which can reduce the formation of scar and corneal astigmatism while enhancing the toughness of the cornea.
Part one biomechanical changes during the healing process of corneal penetrating injury in rabbits
Objective: To study the changes of corneal biomechanics at different time points after corneal penetrating injury in rabbits with suture suture suture
Methods: a total of 40 rabbits were made to model the central corneal perforating injury suture. They were randomly divided into 8 groups, 5 in each group. They were respectively taken at 1 weeks, 2 weeks, 3 weeks, 4 weeks, 5 weeks, 6 weeks, 7 weeks after operation, and 8 corneas were taken from 8 wounds. Tensile test was carried out on BOSE electroforce3220-AT biomechanical test machine.
Results: with the increase of postoperative time, the pulling force of rabbit corneas increased gradually, and then gradually stabilized after 6 weeks. There was statistically significant difference between any two time points at the first 6 weeks (P < 0.01), but there was no significant difference between 6 weeks and 7 weeks (P0.05).
Conclusion: 6 weeks after corneal penetrating injury in rabbits, it has reached a great ability to resist tension, and it is the best time to dismantle the line.
Changes of corneal markers during the healing process of corneal penetrating injury in the second part of rabbits
Objective: to detect and analyze the changes of keratocan, vimentin, CD90 and alpha -SMA marker proteins in cornea at different time points after penetrating injury of cornea in rabbits, so as to observe corneal scar formation at maximum pulling force, and provide reference for optimal suture time after clinical corneal suture.
Methods: 32 rabbits produced central corneal penetrating injury model were randomly divided into 8 groups, 4 rats in each group, respectively after 1 weeks, 2 weeks, 3 weeks, 4 weeks, 5 weeks, 6 weeks, 7 weeks, 8 weeks after complete cornea, using the method of RT-PCR keratocan in the cornea, to detect the time in vimentin, CD90, expression of -SMA alpha gene. Then, through the determination of vimentin in experimental corneal immunohistochemistry, content of alpha -SMA protein.
Results: RT-PCR results showed that the wound healing of corneal stromal cell markers in the process of keratocan with the growth of its expression gradually decreased in rabbit corneal penetrating wound suture after 6 weeks before significant decline, after 6 weeks the expression gradually stable. At the same time expression of fibroblasts and muscle fibroblast markers CD90 and alpha -SMA, and the expression gradually increased with the extension of time, the first 6 Zhou Zenggao obviously after 6 weeks. The protein expression gradually steadily from their respective after 1 to 6 weeks between the 22 was statistically significant (P < 0.01), 6 to 8 weeks between the 22 was not statistically significant (P0.05). With the extension the time after operation, the expression of vimentin increased gradually after 1 to 6 weeks between the 22 comparison difference (P < 0.01).6 weeks compared with 7 weeks of no statistical significance (P0.05). Immunohistochemical data show: with the observation after operation The extension of muscle fiber cell marker expression of alpha -SMA increased gradually, and at 6 weeks after operation. The most significant change compared with the former two arbitrary five time points were statistically significant (P < 0.01). The expression of mesenchymal cell marker vimentin was first increased and then decreased gradually and the trend. After 3 weeks the highest expression level.
Conclusion: corneal stromal cells gradually decrease and become fibroblasts or myofibroblasts in healing process of corneal penetrating injury. Corneal stromal cell transformation tends to be stable at 6 weeks after operation.

【学位授予单位】：河北医科大学
【学位级别】：硕士
【学位授予年份】：2012
【分类号】：R772.2

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