低强度半导体激光照射对豚鼠鼓膜穿孔愈合的作用

Effects of Low-power Semiconductor Laser Irradiation on Healing of Tympanic Membrane Perforations of Guinea Pigs

目的探讨不同照射条件下波长635 nm半导体激光照射对外伤性鼓膜穿孔愈合过程的影响。方法39只健康豚鼠随机分为A、B、C 3组,每组13只,手术显微镜下于双耳鼓膜紧张部后上象限,行约1.5 mm×2.0 mm椭圆形中央性穿孔,保留锤骨柄及鼓环组织。半导体激光分别照射各组豚鼠一侧鼓膜,每次照射10 min,能量密度分别为27.07 J/cm2(A组)、7.43 J/cm2(B组)、3.72 J/cm2(C组),每日1次,共9次。照射侧随机选择左侧或右侧,对侧作为对照不做任何处理。手术显微镜下观察穿孔,记录其中8只豚鼠双侧穿孔的愈合时间。双侧穿孔愈合后处死豚鼠。每组另外5只豚鼠分别在穿孔后第3、5、7、9和11天被处死。取鼓膜及鼓膜附着处组织,常规石蜡切片HE染色,光镜下观察鼓膜厚度及血管增生情况。结果3组对照侧鼓膜穿孔平均愈合时间10.92 d,鼓膜平均厚度114.05μm,A组、B组、C组实验侧穿孔平均愈合时间分别为11.25,9.00和10.50 d,鼓膜厚度分别为142.89、214.28和135.02μm。B组实验侧与其对照侧及与A组、C组实验侧比较,穿孔愈合时间缩短及鼓膜厚度增加,差异有显著意义(P(0.05);穿孔愈合后血管反应增生程度各组间比较,差异无显著意义(P(0.05)。结论波长635 nm半导体激光,能量密度为7.43 J/cm2,每日照射1次,每次10 min,共9 d,可以缩短豚鼠外伤性鼓膜穿孔愈合时间。

Objective To investigate the effects at different doses of low-power 635 nm semiconductor laser irradiation on healing process of tympanic membrane perforations. Methods Thirty-nine healthy guinea pigs were randomly and equally divided into three groups （A, B, C）. Standard otomicrosurgical techniques were used to create bilateral perforations （ 1.5 mm× 2. 0 mm） in the posterosuperior quadrants of the tympanic membranes,leaving the fibrous annulus and the portion of the tympanic membrane covering the malleus intact. Three groups respectively received low-power semiconductor laser irradiation whose doses were 27.07 J/cm^2 （ group A） ,7.43 J/cm^2 （ group B） and 3.72 J/cm^2 （ group C） ,once daily for 10 min, 9 times in all. The irradiated side was selected randomly and the other side was left untreated for comparison. The ears were examined under an operating microscope and 8 of them were recorded the healing time of the tympanic membrane perforations then sacrificed. To examine the healing process in different periods, the other 5 animals in each group were sacrificed 3, 5, 7, 9 and 11 days, respectively, after the creation of the perforations. The intact tympanic membranes with bony annulus were harvested, stained with hematoxylin and eosin, and examined under light microscope. Histologically, the thickness of the tympanic membrane was measured, and neovascularization of the fibrous layer was scored. Results The mean spontaneous healing period of the tympanic membranes of the untreated sides in three] groups was 10. 92 days, and the mean thickness of the tympanic membranes was 114. 05μm. The mean perforation closure time of the treated sides was 11.25 days in group A, 9. 00 days in group B and 10. 50 days in group C. The mean thickness of the tympanic membranes of the treated side was 142. 89μm in group A, 214. 28 μm in group B and 135.02 μm in group C. According to the perforation closure time and the thickness of the tympanic membranes, the difference between the treated side and the control side in group B was significant and the difference among the three treated groups was also significant, group B was different from groups A and C （P 〈 0. 05 ）. The difference of scores between groups was not significant（P 〉 0.05）. Conclusions Low-power semiconductor laser （635 nm） whose energy density was 7.43 J/cm^2, once daily for 10 min, 9 times in all, could accelerate the closure of acute tympanic membrane perforations of guinea pigs, and promote the thickness of the healing tympanic membranes.