中耳胆脂瘤中核因子-κB的表达与活化

目的研究中耳胆脂瘤中核因子-κB(nuclearfactorkappaB,NF-κB)的表达与活化,深入阐明胆脂瘤的发病机制。方法中耳手术中收集21例中耳胆脂瘤组织及8例正常外耳道皮肤组织,分别采用免疫组化及凝胶电泳迁移阻滞法(electrophoreticmobilityshiftassay,EMSA)检测2种组织NF-κB的蛋白表达分布及DNA结合活性,并进一步以胆脂瘤鳞屑刺激人角质形成细胞系HaCaT,观察细胞NF-κB的活性变化。结果胆脂瘤上皮组织中NF-κB的表达强度显著高于正常表皮组织,其阳性细胞平均积分吸光度分别为0·168±0·051、0·088±0·019(t=4·211,P<0·01),部分胆脂瘤(12/21)上皮细胞出现明显NF-κB的核转位;EMSA结果显示胆脂瘤组电泳带相对密度扫描值平均为(16·5±10·1)%,正常皮肤组则为(1·38±1·24)%,提示胆脂瘤组织中NF-κB的DNA结合活性显著高于正常皮肤组织(t=3·600,P=0·014);在胆脂瘤鳞屑刺激下,HaCaT细胞出现NF-κB的活化,其活性变化与鳞屑组织呈剂量依赖关系。结论NF-κB在胆脂瘤组织中存在异常活化,核因子-κB可能在胆脂瘤的发生和持续发展中起重要作用。

Expression and activation of nuclear factor-κB in middle ear cholesteatoma

OBJECTIVE: To explore the expression and activation of NF-kappaB in middle ear cholesteatoma. METHODS: The protein expression of NF-kappaB p65 in 21 middle ear cholesteatoma tissues and 8 normal external ear canal skin obtained in middle ear surgery were examined by immunohistochemitry; NF-kappaB DNA binding activity in these two kinds of tissues were also detected by electrophoretic motility shift assay (EMSA). The influence of cholesteatoma debris on the NF-kappaB DNA binding activity of HaCat cell were further analyzed. RESULTS: All epithelial cell of cholesteatoma revealed a relatively abundant plasm expression of NF-kappaB p65 protein, among which 12 cases showed nuclear positive expression. In contrast,the normal skin epithelium only revealed a sparse plasm distribution of NF-kappaB protein. The levels of NF-kappaB p65 protein expression in the epithelium of middle ear cholesteatoma tissue and normal skin were 0.168 +/- 0.051, 0.088 +/- 0.019 (t = 4.211, P < 0.01), respectively. The NF-kappaB DNA binding activities of cholesteatoma [(16.5 +/- 10.1)%] were also higher than those in normal skin [(1.38 +/- 1.24)%, t = 3. 600, P = 0.014]. The NF-kappaB DNA binding activity of HaCat cell increased when exposed to cholesteatoma debris in a dose dependent manner. CONCLUSION: NF-kappaB might be an important factor which was involved in the occurrence and development of cholesteatoma.