ABSTRACT
BACKGROUND:Insulin-like growth factor-1 (IGF-1) is an important mitogen and an indispensable regulator during normal hair cell development. Extracellular signal regulated kinase 1/2 (ERK1/2) is also expressed in mammalian vestibular organs.OBJECTIVE: To investigate the changes of the expression and the distribution of IGF-1, IGF-1 receptor (IGF-1R) and ERK1/2 in guinea pig's vestibular epithelium following gentamycin injury.DESIGN: A randomly controlled study.SETTING: Department of Otorhinolaryngology, General Hospital of Chengdu Military Area Command of Chinese PLA.MATERIALS: Twenty healthy and adult guinea pigs, weighing 300 to 350 g, provided by the Experimental Animal Center,Fourth Military Medical University of Chinese PLA, were randomly divided into four experimental groups and a control group with 4 in each group.METHODS: The experiment was performed at Department of Otorhinolaryngology Research Laboratory of Xijing Hospital,Fourth Military Medical University of Chinese PLA from January 2002 to May 2002. In the experimental groups,gentamycin was intraperitoneally administered daily (80 mg/kg) for 10 consecutive days. For the control group, 1 mL of 0.9% sterile saline was administered in the same way. The guinea pigs, in which unsteady gait or nystagmus appeared,could be involved in the further experiments. Before being sacrificed, the animals' gait, nystagmus and the amount of food-intake were observed every day. The animals were anesthetized deeply with 50 mg/kg pentobarbital 1, 7, 14 or 21days after the last gentamycin administration and then decapitated. Bilateral otic vesicles were harvested and immersed in 4% paraformaldehyde. Then the specimens were decalcified in 10% ethylenediamine tetraacetic acid (EDTA),thereafter embedded in OCT gel and serially sectioned at a thickness of 10 μm in the cryostat. The behavioral changes of guinea pigs were observed. The morphological changes of vestibular epithelium were examined by hematoxylin and eosin (HE) staining. The expression and distribution changes of IGF-1/1R and ERK1/2 were investigated immunohistochemically. MAIN OUTCOME MEASURES: The behavioral, morphological, expression and distribution changes of IGF-1/1R and ERK1/2 of guinea pigs in each group.RESULTS: Twenty involved guinea pigs entered the stage of final analysis. ① All the guinea pigs' vestibular functions were impaired after gentamycin treatment, then partially restored without any pharmaceutical treatment. ②Morphological injury was obvious after gentamycin treatment, and improved 1 week later. ③The expression of IGF-1/1R was low in the control group, and in the 1-day group it increased significantly to its maximum. After that, its expression decreased gradually, but was still higher in the 21-day group than that in the control group. There were significant differences in the expression of IGF-1/1R among different groups (F =51.8,45.7,P ＜ 0.05). The expression changes of IGF-1 and its receptor were similar. ④The expression of ERK1/2 was low in the control group, and increased gradually after gentamycin toxicity. In the 7-day group, the immunoreactivity reached its maximum. Then the levels of ERK1/2 decreased gradually, but were still higher in the 21-day group than that in the control group. There were significant differences in the expression of ERK1/2 among different groups (F =103.7,106.4, P ＜ 0.01), but no significant differences existed in the expression between ERK1 and ERK2 among different groups (P ＞ 0.05).CONCLUSION: The expression of IGF-1/1R and ERK1/2 in vestibular epithelium increased after gentamycin treatment,and IGF-1 may play an important role as an endogenous mitogen through a paracrine or autocrine manner in the early stage of hair cell self-repair of guinea pigs. ERK1/2 may play an important role in signal transduction during vestibular hair cell self-repair after gentamycin toxicity in guinea pigs.
ABSTRACT
Objective To investigate the common complications related to glomus jugulare tumors surgery,their influencing factors,and to search for the effective treatments of these complications.Methods A retrospective study was undertaken on the complications observed in 47 patients with glomus jugulare tumors who underwent 51 times of operation via trans external auditory canal approach,the retroauricular approach,and modified infratemporal fossa approach type A.All cases were followed up over 1 month after surgery.Results Of 51 cases,the most frequent complication was total conductive hearing loss which occurred in 21 cases(41.2%),facial paralysis was found in 15 cases(29.4%) and lower cranial nerve palsy was found in 14 cases(27.5%) after one month.Other complications were cerebrospinal fluid(CSF) leak,hearing disability and vertigo,each in 3 cases(5.9%);cerebral infarction,partial auricle necrosis and parotid gland fistula,each occurred in one case(2.0%).Pre-operative selective embolization of feeding vessels can reduce intraoperative blood loss significantly in most cases.Effective hemostasis and hypotensive anesthesia during operation were the important ways to prevent complications and hematoma within operating field.CSF leak in this series was an uncommon complication.Two cases with CSF leak from the wound had been successfully controlled with conservative treatment.One case with CSF leak required surgical management.None of these patients developed meningitis.Conclusions There is a low level of serious post-operative complications in operation on glomus jugulare tumor.Factors found to be relevant to post-operative complications are tumor type and tumor size.The key factors to avoid the complications include surgical experience,surgical skill and preoperative evaluation of patients′ imaging information.