目的:青光眼是一种多因素相关的视神经病变,致盲率高,其发病机制复杂,目前尚未明确。高眼压是目前唯一可调控的、与青光眼的发病密切相关的危险因素。本研究通过运用环角膜缘缝合与小梁网联合巩膜静脉激光光凝2种不同的方法建立慢性高...目的:青光眼是一种多因素相关的视神经病变,致盲率高,其发病机制复杂,目前尚未明确。高眼压是目前唯一可调控的、与青光眼的发病密切相关的危险因素。本研究通过运用环角膜缘缝合与小梁网联合巩膜静脉激光光凝2种不同的方法建立慢性高眼压大鼠模型,比较2种模型的眼压升高程度和高眼压持续时间,视网膜形态损伤和视网膜神经节细胞(retinal ganglion cells,RGCs)损伤程度,以及超微结构改变等。方法:建立2种慢性高眼压模型,分为环角膜缘缝合组(缝合组,用10/0尼龙线沿角巩膜缘缝合)和激光光凝组(激光组,激光灼烧小梁网联合巩膜外静脉),并以其对侧眼作为对照组。观察并定期规律监测2组大鼠的眼压变化。采用大鼠视网膜切片HE染色观察2种慢性高眼压模型对视网膜和视神经病理学的影响,透射电镜(transmission electron microscope,TEM)观察慢性高眼压模型超微结构中线粒体形态的变化,大鼠视网膜铺片Brn3b抗体免疫荧光染色特异性标记RGCs并计数,蛋白质印迹法检测凋亡相关蛋白caspase-3的表达以明确RGCs的凋亡情况。结果:与对照组相比,缝合组与激光组大鼠眼压均明显升高(均P<0.05),其中缝合组的眼压最高升高1.5倍,眼压显著升高持续8周;激光组的眼压最高达对照组的2倍,持续12周。2组都会导致RGCs丢失,与Brn3b染色的结果相符,2组caspase-3表达水平均升高(均P<0.05)。而在TEM下,2组RGCs中的线粒体形态均变为碎片化,从正常的长条形变小、变圆。与激光组相比,缝合组视网膜形态学的病理变化较轻微。结论:环角膜缘缝合可建立有效的慢性高眼压模型,诱导与激光光凝模型相似的青光眼性病理改变,但病理改变较激光光凝轻微。相较于激光光凝建模,环角膜缘缝合法对于设备要求和操作能力要求更低。展开更多
Retinal progenitor cells （RPCs） are neural stem cells able to differentiate into any normal adult retinal cell type, except for pigment epithelial cells. Retinoic acid （RA） is a powerful growth/differentiation fac...Retinal progenitor cells （RPCs） are neural stem cells able to differentiate into any normal adult retinal cell type, except for pigment epithelial cells. Retinoic acid （RA） is a powerful growth/differentiation factor that generally causes growth inhibition, differentiation and/or apoptosis. In this study, we demonstrate that RA not only affects mouse RPC differentiation but also improves cell survival by reducing spontaneous apoptotic rate without affecting RPC proliferation. The enhanced cell survival was accompanied by a significant upregulation of the expression of protein kinase A （PKA） and several protein kinase C （PKC） isoforms. Treatment of cells grown in RA-free media with 8-bromoadenosine3＇,5＇-cyclic monophosphate, a known activator of PKA, resulted in an anti-apoptotic effect similar to that caused by RA; whereas the PKA inhibitor N-[2-（p-bromocinnamylamino）ethyl]-5-isoquinolinesul- fonamide dihydrochloride led to a significant （-32%） increase in apoptosis. In contrast, treatment of RPCs with any of two PKC selective inhibitors, 2,2＇,3,3＇,4,4＇-hexahydroxy-1,1 ＇-biphenyl-6,6＇-dimethanol dimethyl ether and bisindolylmaleimide XI, led to diminished apoptosis; while a PKC activator, phorbol 12-myristate 13-acetate, increased apoptosis. These and other data suggest that the effect of RA on RPC survival is mostly due to the increased anti-apoptotic activity elicited by PKA, which might in turn be antagonized by PKC. Such a mechanism is a new example of tight regulation of important biological processes triggered by RA. Although the detailed mechanisms remain to be elucidated, we provide evidence that the pro-survival effect of RA on RPCs is not mediated by changed expression of p53 or bcl-2, and appears to be independent of 15-amyloid, Fas ligand, TNF-α, ganglioside GM1 and ceramide C 16-induced apoptotic pathways.展开更多
基金supported by the National Natural Science Foundation(81700838)the Natural Science Foundation of Hunan Province(2020JJ4789)the Scientific Research Project of Health Commission of Hunan Province(202307027224),China.
文摘目的:青光眼是一种多因素相关的视神经病变,致盲率高,其发病机制复杂,目前尚未明确。高眼压是目前唯一可调控的、与青光眼的发病密切相关的危险因素。本研究通过运用环角膜缘缝合与小梁网联合巩膜静脉激光光凝2种不同的方法建立慢性高眼压大鼠模型,比较2种模型的眼压升高程度和高眼压持续时间,视网膜形态损伤和视网膜神经节细胞(retinal ganglion cells,RGCs)损伤程度,以及超微结构改变等。方法:建立2种慢性高眼压模型,分为环角膜缘缝合组(缝合组,用10/0尼龙线沿角巩膜缘缝合)和激光光凝组(激光组,激光灼烧小梁网联合巩膜外静脉),并以其对侧眼作为对照组。观察并定期规律监测2组大鼠的眼压变化。采用大鼠视网膜切片HE染色观察2种慢性高眼压模型对视网膜和视神经病理学的影响,透射电镜(transmission electron microscope,TEM)观察慢性高眼压模型超微结构中线粒体形态的变化,大鼠视网膜铺片Brn3b抗体免疫荧光染色特异性标记RGCs并计数,蛋白质印迹法检测凋亡相关蛋白caspase-3的表达以明确RGCs的凋亡情况。结果:与对照组相比,缝合组与激光组大鼠眼压均明显升高(均P<0.05),其中缝合组的眼压最高升高1.5倍,眼压显著升高持续8周;激光组的眼压最高达对照组的2倍,持续12周。2组都会导致RGCs丢失,与Brn3b染色的结果相符,2组caspase-3表达水平均升高(均P<0.05)。而在TEM下,2组RGCs中的线粒体形态均变为碎片化,从正常的长条形变小、变圆。与激光组相比,缝合组视网膜形态学的病理变化较轻微。结论:环角膜缘缝合可建立有效的慢性高眼压模型,诱导与激光光凝模型相似的青光眼性病理改变,但病理改变较激光光凝轻微。相较于激光光凝建模,环角膜缘缝合法对于设备要求和操作能力要求更低。
文摘Retinal progenitor cells （RPCs） are neural stem cells able to differentiate into any normal adult retinal cell type, except for pigment epithelial cells. Retinoic acid （RA） is a powerful growth/differentiation factor that generally causes growth inhibition, differentiation and/or apoptosis. In this study, we demonstrate that RA not only affects mouse RPC differentiation but also improves cell survival by reducing spontaneous apoptotic rate without affecting RPC proliferation. The enhanced cell survival was accompanied by a significant upregulation of the expression of protein kinase A （PKA） and several protein kinase C （PKC） isoforms. Treatment of cells grown in RA-free media with 8-bromoadenosine3＇,5＇-cyclic monophosphate, a known activator of PKA, resulted in an anti-apoptotic effect similar to that caused by RA; whereas the PKA inhibitor N-[2-（p-bromocinnamylamino）ethyl]-5-isoquinolinesul- fonamide dihydrochloride led to a significant （-32%） increase in apoptosis. In contrast, treatment of RPCs with any of two PKC selective inhibitors, 2,2＇,3,3＇,4,4＇-hexahydroxy-1,1 ＇-biphenyl-6,6＇-dimethanol dimethyl ether and bisindolylmaleimide XI, led to diminished apoptosis; while a PKC activator, phorbol 12-myristate 13-acetate, increased apoptosis. These and other data suggest that the effect of RA on RPC survival is mostly due to the increased anti-apoptotic activity elicited by PKA, which might in turn be antagonized by PKC. Such a mechanism is a new example of tight regulation of important biological processes triggered by RA. Although the detailed mechanisms remain to be elucidated, we provide evidence that the pro-survival effect of RA on RPCs is not mediated by changed expression of p53 or bcl-2, and appears to be independent of 15-amyloid, Fas ligand, TNF-α, ganglioside GM1 and ceramide C 16-induced apoptotic pathways.
