ABSTRACT
OBJECTIVES: methyl-D-aspartate NMDA receptor (NMDAR) and aquaporin 4 (AQP4) are involved in the molecular cascade of edema after traumatic brain injury (TBI) and are potential targets of studies in pharmacology and medicine. However, their association and interactions are still unknown. MATERIALS AND METHODS: We established a rat TBI model in this study. The cellular distribution patterns of AQP4 after inhibition of NMDAR were determined by Western blotting and immunoreactive staining. Furthermore, the regulation of NMDA receptor 1 by AQP4 was studied by injection of a viral vector targeting AQP4 by RNAi into the rat brain before TBI. RESULTS: The results suggest that AQP4 protein expression increased significantly (P<0.05) after TBI and was down-regulated by the NMDAR inhibitor MK801. This decrease could be partly reversed using the NMDAR agonist NMDA. This indicated that AQP4 mRNA levels and protein expression are regulated by the NMDA signaling pathway. By injection of AQP4 RNAi viral vector into the brain of TBI rat models, we found that the mRNA and protein levels of NMDAR decreased significantly (P<0.05). This suggested that NMDAR is also regulated by AQP4. CONCLUSION: These data suggested that the inhibition of AQP4 down-regulates NMDAR expression, which might be one of the mechanisms involved in edema after TBI.
ABSTRACT
Most patients diagnosed with neurofibromatosis type 2 (NF2) have bilateral vestibular schwannomas (VS). Through reviewing surgical method and clinical outcomes, we tried to find out a strategy for treatments in NF2 patients with VS.We retrospectively reviewed patients diagnosed pathological NF2 and have had microsurgery (MS) for VS in the PLA Army General Hospital. Seventeen patients were included from January 2000 to December 2016. Fifteen patients had progressive hearing impairment, and 7 ears were totally deaf. Computed tomography and magnetic resonance imaging were used for preoperative and postoperative evaluation. House-Brackmann (H-B) classification was used to evaluate facial function, and the hearing outcome was classified according to American Academy of Otolaryngology-Head and Neck Surgery (AAO-HNS) hearing classification system. The outcomes included functional hearing, facial function, and complications.In the 17 patients, 9 were men, and the mean age was 27.2 years old. The mean duration of disease was 38.4 months. Twenty-six VS were excised. Nine patients with bilateral VS and unilateral surgery had repeated surgery for the contralateral tumor after 3 to 12 months. The hearing preservation rate was 41.6%. In the 26 excisions for VS, 24 had intact facial nerve. In the other 2 tumor excision, damaged facial nerves had head-to-head adhesion using biological fibrin glue. The rate of facial nerve function preservation was 60%. No mortality or major complication was reported. The follow-up time ranged from 11 to 78 months with a mean value of 39 months.MS is an effective treatment for NF2 patients with VS. The operation for bilateral VS should be staged according to tumor size and bilateral hearing function. However, methods on how to preserve functional hearing and facial function remain the issue. Further randomized controlled studies are needed to find out a better treatment for NF2 patients with VS according to the overall condition.
