目的 本实验采用光损伤小鼠模型，探讨杞菊地黄丸联合美托洛尔的光感受器细胞保护效应及视网膜重塑相关机制。方法 采用BALB/c小鼠，随机分为正常对照组、光损伤模型组、美托洛尔治疗组、杞菊地黄丸治疗组及杞菊地黄丸联合美托洛尔治疗组，给药一周后进行24 h暗适应，末次给药后15 min以10 000 lux白光光照30 min对小鼠进行造模，3天后采用视网膜电图（electroretinogram,ERG）进行视网膜功能分析，7 d后采用光学相干断层扫描（optical coherence tomography,OCT）对视网膜结构进行分析并测量视网膜外核层（outer nuclear layer,ONL）厚度，最后进行眼球取材、切片、病理学及免疫组织化学分析进一步明确各组视网膜光感受器细胞、双极细胞、水平细胞及Müller细胞病理改变情况。结果 （1）OCT、ONL厚度及HE染色分析结果表明，与正常对照组完整的视网膜形态及ONL厚度相比较，光损伤模型组小鼠视网膜ONL结构受损严重，ONL厚度显著降低（P < P < 0.05）；与光损伤模型组相比较，美托洛尔及杞菊地黄丸治疗组均存在不同程度的视网膜ONL结构破坏，其中美托洛尔给药组视网膜ONL形态与光损伤模型组结果相似，杞菊地黄丸治疗组视网膜尚可见视网膜ONL结构层次，ONL厚度测量结果表明美托洛尔与杞菊地黄丸给药组ONL厚度较模型组显著增加（P < P < 0.05）；与光损伤模型组和美托洛尔治疗组及杞菊地黄丸治疗组相比，杞菊地黄丸联合美托洛尔给药组小鼠视网膜结构清晰，ONL厚度显著增加（P < 0.05）。（2）ERG分析结果表明，正常对照组小鼠视网膜电图a波及b波振幅随着刺激增强而上升；与正常对照组相比较，光损伤模型组小鼠a波及b波振幅显著降低（P < 0.05）；与光损伤模型组相比，美托洛尔治疗组小鼠视功能未见改善，杞菊地黄丸组小鼠视网膜电流图振幅增加（P < 0.05）；与光损伤模型组和美托洛尔治疗组及杞菊地黄丸治疗组相比较，杞菊地黄丸联合美托洛尔治疗组a波及b波振幅显著增加（P < 0.05）。（3）免疫组织化学分析结果表明，正常对照组小鼠视网膜光感受器细胞外节视紫红质（rhodopsin,RHO）和中波敏感视蛋白（mid-wavelength sensitive cone opsin,M-opsin），双极细胞标志蛋白激酶Cα（protein kinase Cα,PKCα），水平细胞标志蛋白钙结合蛋白D（Calbindin D）以及Müller细胞标志蛋白胶质纤维酸性蛋白（glial fibrillary acidic protein,GFAP）免疫阳性正常；与正常对照组相比较，光损伤模型组小鼠视网膜上述神经元标志蛋白免疫阳性染色显著减弱甚至消失，GFAP表达模式异常，提示胶质异常增生；与光损伤模型组相比较，美托洛尔治疗组上述视网膜神经元免疫阳性并无差异，杞菊地黄丸治疗组视网膜双极细胞和水平细胞免疫阳性显著增强，但光感受器细胞标志蛋白和Müller细胞免疫阳性并无差异；与模型组及美托洛尔治疗组和杞菊地黄丸治疗组相比较，杞菊地黄丸联合美托洛尔治疗组视网膜光感受器细胞、双极细胞、水平细胞标志蛋白免疫阳性显著增强，GFAP免疫阳性减弱。结论 杞菊地黄丸联合美托洛尔干预对光感受器细胞结构及功能具有显著的保护效应，可能与其促进视网膜修复性重塑相关。

Objective The current study investigated the potential effects of combined treatment of Qiju Dihuang pill and metoprolol on photoreceptor degeneration and associated retinal remodeling in a mouse model of light-induced retinal degeneration.Methods BALB/c mice were randomly divided into five experimental groups including normal controls unexposed to bright light (No BL), bright light-exposed vehicle-treated mice (BL_Vehicle), bright light-exposed mice treated with metoprolol (BL_MTP)， bright light-exposed mice treated with Qiju Dihuang pill (BL_QJD) and bright light-exposed mice treated with QJD and MTP (BL_QJD+MTP). After a week of oral administration of the indicated treatment, mice were dark adapted for 24 h before illumination. Indicated treatment was administered 15 min before bright light exposure. Bright light was applied at the intensity of 10,000 lux for 30 min. Electroretinogram (ERG) and optical coherence tomography (OCT) imaging were performed 3 d and 7 d after light exposure to reveal the retinal function and structure, respectively. Meanwhile, the thickness of outer nuclear layer (ONL) was evaluated. Eyes were enucleated after ERG and OCT evaluation and subject to paraffin or frozen embedding, which was followed by immunohistochemical analyses to assess light-induced changes in photoreceptor cells, bipolar cells, horizontal cells and Müller cells.Results (1) OCT, HE staining and ONL thickness analyses showed that compared to that from No BL, in which the intact retinal structure and normal ONL thickness were observed, the retina structure of BL_Vehicle was severely damaged and the thickness of ONL was significantly decreased (P < 0.05); Compared to that from BL_Vehicle, the ONL thickness of BL_MTP and BL_QJD mice was moderately increased (P < 0.05) although the photoreceptor structure was visibly impaired. Compared to that from BL_Vehicle, BL_MTP and BL_QJD, combined treatment of Qiju Dihuang pill and metoprolol resulted in marked preservation of the retinal structure and the ONL thickness was significantly increased (P < 0.05). (2) Functional assessments of the retina by ERG revealed that the amplitude of electroretinogram in No BL was elevated with the increase of light stimulation, whereas such response to light stimulation was not seen in BL_vehicle. Meanwhile, a wave and b wave amplitudes in the BL_Vehicle were significantly decreased compared to that from the No BL (P < 0.05). Compared to BL_vehicle, no difference in visual function was observed in BL_MTP, while moderate improvement in the visual function was observed in BL_QJD (P < 0.05); Compared to that from BL_Vehicle, BL_MTP and BL_QJD, significantly increased a wave and b wave amplitudes were observed in BL_QJD+MTP (P < 0.05).(3)Immunohistochemical assessment revealed that rhodopsin (RHO), mid-wavelength sensitive cone opsin (M-opsin), protein kinase C alpha (PKCα), calcium binding protein D (Calbindin D) and glial fibrillary acidic protein(GFAP) labeled rod cells, cone cells, bipolar cells, horizontal cells and Müller cells in a normal fashion in the No BL. Compared to that from No BL, immunopositivity of aforementioned retinal neurons was no longer present in the central retina and only residual staining was detected in the BL_Vehicle. Meanwhile, reactive gliosis of Müller cells was revealed by exaggerated immunopositivity of GFAP in the BL_Vehicle. Compared to that from the BL_Vehicle, enhanced labeling of PKCα and Calbindin D was observed in BL_QJD, but RHO and M-opsin immunopositivity was barely detected and reactive gliosis was observed. In contrast to that observed in BL_Vehicle, BL_MTP and BL_QJD, combined treatment of Qiju Dihuang pill and metoprolol resulted in significantly enhanced immunopositivity of neuronal markers. In the meantime, immunopositivity of GFAP was evidently decreased.Conclusions Combined treatment of Qiju Dihuang pill and metoprolol not only maintains the structural and functional integrity of photoreceptor cells, it also promotes reparative retinal remodeling during the course of retinal degeneration