界嵴连接蛋白43分布的增龄性变化与电传导异向性的关系

为探讨界嵴组织连接蛋白 4 3(Cx4 3)的增龄性变化及其与电传导异向性的关系 ,采用新西兰幼年白兔 (2 0～ 30天 )、成年兔 (6～ 8月 )、老年兔 (2 6～ 2 8月 )界嵴组织行Masson染色和免疫组化检测Cx4 3。与各年龄组月龄相配对的家兔各 7只 ,采用玻璃微电极技术测量界嵴纵向 (VL)及横向 (VT)传导速度。结果 :界嵴组织可见P样细胞单个或成群分布。各年龄组Cx4 3阳性表达面积无差别 ,幼年兔Cx4 3表达多在细胞的侧 侧连接上 ;成年兔端 端表达比侧 侧表达为多 ;而老年兔则以端 端连接表达为主。随着年龄增加 ,各年龄组VT 和VL 也发生改变 ,传导异向性(VL/VT)明显加大。端 端 /侧 侧Cx4 3阳性面积比率与VL/VT 明显相关 (r =0 .90 3)。结论 :界嵴Cx4 3表达的增龄性变化与电传导异向性改变有关 ,后者在特定的生理或病理条件下可能是界嵴产生和 /或参与房性心律失常的物质基础。

The Relationship Between Distribution Pattern of Cx43 and Anisotropic Conduction Properties of the Crista Terminalis With Aging

To investigate the relationship between expression of connexin 43 and the conduction properties of the crista terminalis (CT) in the aging process . Paraffin sections of CT tissue of rabbits at the age of 20～30 days (underage group , n=7) , 6～8 months (adult group , n=7) , 26～28 months (aged group , n=7) were stained by masson trichrome and immunohistochemistry . Longitudinal conduction velocity ( V L) and transverse conduction velocity (V T) were measured by conventional glass microelectrode technique . Results:P-like cells were found in the CT tissue which distributed in either separate or congregate manner . There were no changes of the percentage of Cx43-positive area in the three groups . However, marked non-uniformities emerged in the sarcolemmal distribution of Cx43 . In the aged group , Cx43-positive puncta were prominently localized at myocyte termini with an apparent reduction at myocyte sides . Correlated with the change of Cx43 spatial distribution , conduction anisotropy (V L/V T) in the aged group and adult group were significantly increased compared to underage group.Variation in Cx43 ends/sides distribution with aging closely matched with variation in V L/V T (r=0.903).Conclusions:The changes of expression pattern of Cx43 with aging were correlated with changes of the conduction properties of the CT. The latent autorhythmicity and conduction properties of the CT may provide the morphologic basis which may be the origin of atrial premature or / and reentrant pathways under the specified condition .