中文摘要：

目的探讨苯肾上腺素预处理对放射损伤早期大鼠颌下腺RT1-A表达的影响。方法取Wistar大鼠27只,随机分为空白对照组、单纯照射组及苯肾上腺素预处理组。预处理组大鼠于照射前半小时腹腔注射苯肾上腺素5mg/kg。应用直线加速器给予大鼠颌下腺区域20Gy X射线照射。照射后7天取大鼠颌下腺组织,应用免疫组织化学法检测各组大鼠颌下腺RT1-A（小鼠抗人HLAⅠ单克隆抗体,抗体浓度为1：200）的定位与表达;应用半定量逆转录聚合酶链法（reverse transcription-polymerase chain reaction,RT-PCR）检测各组大鼠颌下腺RT1-A mRNA的表达。结果免疫组织化学结果显示：在空白对照组RT1-A主要表达于腺泡细胞及导管细胞的胞浆和胞膜;单纯照射组RT1-A在腺泡细胞胞膜和细胞间质的表达增加;而苯肾上腺素预处理组RT1-A在腺泡细胞胞膜及间质的表达较单纯照射组明显减少。RT-PCR结果显示：单纯照射组RT1-A mRNA的表达较空白对照组增加了40.14%（P〈0.05）,苯肾上腺素预处理组RT1-A mRNA的表达较单纯照射组下降了45.02%（P〈0.05）。结论放射线照射损伤早期可使大鼠颌下腺RT1-A的表达增加,苯肾上腺素能够下调放射损伤后RT1-A的表达,提示a1-肾上腺素受体活化参与了颌下腺放射损伤后免疫调节,为探寻防治颌下腺放射损伤的方法提供了新策略。

英文摘要：

Objective To investigate the influence of pretreated phenylephrine on the expression of RT1-A in irradiated submandibular gland in rat in early phase.Methods 27 Wistar rats were randomly divided into three groups： the control group,the simple irradiated group,and the irradiated group with pretreated phenylephrine,in which the rats were pretreated with phenylephrine（5mg/kg） through intraperitoneal injection 30 minutes before irradiation.20 Gy X-ray irradiation was delivered to the submandibular region by applying a medical linear accelerator,and submandibular glands were removed on seven days after irradiation.The distribution of RT1-A（mice anti human HLA Ⅰ monoclonal antibody（diluted 1：200） was then detected by immunohistochemical assay,and the mRNA expression of RT1-A was determined by reverse transcription polymerase chain reaction（RT-PCR）.Results The distribution of RT1-A was mainly located in the cytoplasm and cytomembrane of both acinar cells and ductal cells in the control group,was increased in the cytomembrane of acinar cells and mesenchyme in the simple irradiated group,and was markedly decreased in the irradiated group with pretreated phenylephrine.Also,results from RT-PCR demonstrated that the expression of RT1-A mRNA was up-regulated 40.14%（P0.05） in the simple irradiated group compared with the control group,but was down-regulated 45.02%（P0.05） in irradiated group with pretreated phenylephrine compared with the simple irradiated group.Conclusion The expression of RT1-A in the rat submandibular gland could be increased after irradiation early stage and could be decreased by phenylephrine pretreatment.These results suggested that the activation of α1-adrenergic receptor signal pathway might be involved in the mechanism of immunological regulation in submandibular gland after irradiated injury,which might provide a new strategy in preventing and treating salivary gland irradiated damage.