局部应用人重组表皮生长因子对中耳创伤修复影响的动物实验研究

Effects of topical application of recombinant human epidermal growth factor on the wound repair of guinea pig middle ears

目的了解局部应用人重组表皮生长因子(rhEGF)对中耳创伤修复的影响和组织愈合特点。方法鼓膜创伤实验组中,30只豚鼠的鼓膜创伤面积为2mm×2mm,局部分别滴注rhEGF、生理盐水及空白对照;中耳黏膜创伤实验组中,将10只豚鼠的鼓膜紧张部切开,用小号中耳粘膜剥离子搔剥鼓室内侧壁粘膜,造成一个范围约为2×3mm的粘膜缺损区,中耳局部分别放置rhEGF明胶海绵粒和生理盐水明胶海绵粒。对两组豚鼠均进行预防性抗感染处理,并在不同时期用电耳镜、光镜及透射电镜对创面的愈合速度及鼓膜形态学的变化进行观察。结果鼓膜创伤实验组中,局部滴注rhEGF20耳的平均愈合时间为(8.5±3.0)d,局部滴注生理盐水20耳的平均愈合时间为(11.8±2.6)d,空白对照20耳的平均愈合时间为(12.8±2.3)d,局部滴注rhEGF的鼓膜创伤愈合速度明显快于生理盐水滴注耳及空白对照耳(P<0.001);滴注rhEGF的鼓膜在创伤后2周时外层的鳞状上皮已增生覆盖创面,内层的扁平上皮增生,两层上皮间未见明显组织结构;滴注生理盐水的鼓膜在创伤后2周时创面见少量鳞状上皮及肉芽疤痕组织;滴注rhEGF耳和滴注生理盐水耳的鼓室黏膜结构均正常。中耳黏膜创伤实验组中,rhEGF滴注耳中有5耳的鼓室粘膜的上皮增生,覆盖部分创伤区表面,创伤区内见纤维组织增生;而滴注生理盐水耳中创伤区胶原纤维组织增生,其表面未见上皮被覆。结论rhEGF能促进创伤鼓膜的组织恢复,对鼓室黏膜的组织形态未造成不良的影响,且中耳局部应用rhEGF后,在短期内不会引起组织钙化及疤痕增生。

Objective To investigate changes of the normal and wounded tissues in the guinea pig middle ear after topical application of recombinant human epidermal growth factor（rhEGF）. Methods In the tym- panic membrane wound group, myringotomy was made in 30 guinea pigs and the wound size was about 2×2mm. rhEGF and physiological saline were topically applied to the left and right ears of 20 guinea pigs, respectively, and in other 10 guinea pigs nothing was topically applied as blank control. In the middle ear mucosa wound group,parstensa myringotomy was performed in 10 guinea pigs and a middle ear mucosa defect of 2mm×3mm in size was surgically created. The middle ear cavities were filled with rhEGF and physiological saline-soaked gelatine sponge, respectively. The guinea pigs in both groups received intramuscular antibiotics prophylactically for 2 weeks. The healing speed and morphological changes of the wounded tympanic membranes and middle ear mucosa were examined with otoscope and studied by light and electron microscopic histology at different time point. Results In the tympanic membrane wound group, the average healing times were 8.5±3.0, 11.8±2.6 and 12.8±2.3 days for the rhEGF, physiological saline and blank comtrol subgroups, respectively, indicating topically applied rhEGF resulted in more rapid healing than applied physiological saline and blank control （p〈0.05）. The external side of the tympanic membrane was covered by squamous epithelium completely and the internal side, with partly regenerated flat epithelial cells after topically applied rhEGF. When topically applied physiological saline, however, only a few squamous epithelial cells but rather abundant granulations and scar tissues were found in the wounded area. In the middle ear mucosa wound group, the stratified ciliated columnar epithelium recovered partly in 5 middle ears of the rhEGF subgroup. In the physiological saline subgroup, however, the stratified ciliated columnar epithelium was absent and replaced by tessellated epithelium and proliferated collagenous fibers. Conclusion Topically applied rh EGF could accelerate healing of the wounded tympanic membrane in guinea pigs and had no adverse effects on the middle ear mucosa, such as tissue calcification and scar formation.