Jang Chul Ho, Cho Yong Bum, Choi Cheol Hee, Park See Young, Pak Sok Cheon
Department of Otolaryngology, Chonnam National University Medical School, Gwangju, Dong-ku, South Korea.
In Vivo. 2007 Nov-Dec;21(6):1043-7.
Sensorineural hearing loss, which is limited to the cochlear basal turn, due to acute or chronic otitis media has been reported in clinical and experimental studies. In the present study, the effect of intratympanic dexamethasone on endotoxin-induced cochlear damage was investigated by measuring the cochlear blood flow and hearing.
Ten male Sprague-Dawley rats were inoculated with lipopolysaccharide (LPS), and divided into 2 groups of five rats each. One hour after intratympanic inoculation, the group A received 40 microl of phosphate-buffered saline (PBS) in the right middle ear cavity, group B received 40 microl of dexamethasone. The treated animals were examined 24 h after inoculation using auditory brainstem response (ABR) and cochlear blood flow (CBF).
The elevated threshold decreased significantly after intratympanic dexamethasone administration compared to the PBS-treated group. Intratympanic dexamethasone administration to the round window of rats led to a statistically significant increase in CBF compared to the PBS-treated group (p <0.05). The response to round window application of prostaglandin E1 (PGE1) in the dexamethasone-treated group was better than in the PBS-treated group.
Our results showed that intratympanic dexamethasone treatment was effective in protecting the function of the cochlea against endotoxin-induced otitis media.
临床和实验研究均报道过，急性或慢性中耳炎导致的感音神经性听力损失局限于耳蜗底转。在本研究中，通过测量耳蜗血流量和听力，研究了鼓室内注射地塞米松对内毒素诱导的耳蜗损伤的影响。
10只雄性Sprague-Dawley大鼠接种脂多糖（LPS），并分为两组，每组5只。鼓室内接种1小时后，A组在右中耳腔注入40微升磷酸盐缓冲盐水（PBS），B组注入40微升地塞米松。接种24小时后，使用听性脑干反应（ABR）和耳蜗血流量（CBF）对处理后的动物进行检查。
与PBS处理组相比，鼓室内注射地塞米松后，升高的阈值显著降低。与PBS处理组相比，向大鼠圆窗鼓室内注射地塞米松导致CBF有统计学意义的增加（p<0.05）。地塞米松处理组对圆窗应用前列腺素E1（PGE1）的反应优于PBS处理组。
我们的结果表明，鼓室内注射地塞米松治疗对内毒素诱导的中耳炎具有保护耳蜗功能的作用。
