| The amniotic membrane transplantation for rebuilding ocular surface is becoming the focus of the ophthalmology however ,so far; it's mechanism is not clear .We stitched the human amniotic membrane on the ocular surface of the rabbit comeas after the excimer laser photo therapeutic keratectomy (PTK) in order to discuss the effect and mechanism of the amniotic membrane on the healing of the comeal wound ,and explore a new way to reduce the haze after PTK. Twenty-seven New Zealand healthy white rabbits without any ocular disease were undergone PTK in the same way (as deep as means). In each rabbit one eye was immediately transplanted the human amniotic membrane which was preserved in 40 C to the comeal surface after PTK,, it's in experimental group and its counter was in the control group without any other treatment So there were 27 eyes in the experimental group and 27 in the control group. Every eye's general condition was observed postoperatively every day. All stitch and the amniotic membrane of the experimental group were removed a week postoperatively The rabbits were killed respectively at 3,5,7days(early stage) and 4,8weeksQate stage)postoperatively. Both comeas of each rabbit were removed at once and undergone examination by light microscopy(LM) and transmission electronic microscopy(ITEM), meanwhile, the thickness of proliferative epitheial 3 cell in the center of cornea was measured and analyzed statistically Haze of all rabbits was observed by slit lamp microscopy and evaluated according to Fantes Grade at 4 and 8 week postoperatively Postoperatively, there was no rejection to the amniotic membrane on the experimental eyes During the early postoperative stage, in both group, multi-layered neonatal comeal epithelial cell which completely covered the laser section within 3 days can be observed with LM; epithelial cells of several sizes appeared in the basal lamina; and in the center of the laser section, the thickness of epitheial cell in the experimental group was significantly less than that in the control group. By the ThM we found increasing kaiyokinesis of comeal epithelial basal cell, cell organ; many flbroblast containing rich cytoplasm and cell organ in the anterior stromal layer of the laser section, and cell present rematkable activity There was more apoptosis cell in the superficial layer of epithelium in the control group than in the experimental group. At the 4th week, comeal epithelial cell covering the laser section in both groups was still light proliferation, however; in the control group there was much neofoimative collagen ananging 馮egularly and cicatricial tissue in the anterior stromal layer. By the ThM, activing flbroblast in the anterior stromal layer could be fouml Less nascollagen and cicatncial tissue could be find in the experimental group than in the control group .At the 8th week postoperatively ,both groups still have not restored the normal thickness of comeal epithelial cell; but in the control group there was more neofoimative in-egular collagen in the anterior stromal layer, and in the experimental group middle quantity collagen fiber and significantly active fibroblast could be observed. Although different levels of haze had appeared since one week 4postoperatively, the degree of it was significantly lower in the experimental group than in the control one (p |
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