Connexins are membrane-spanning proteins that form membrane channels and hemichannels. They are involved in the cellular communication and in the maintenance of tissue homeostasis. Recent studies in humans and animals have demonstrated that the expression and distribution of Cx43, the most studied connexin, can change during aging. However, the research on the involvement of the other connexins in cardiac and hepatic aging is, at present, still very poor. Hence, the aim of this study is to evaluate the expression of Cx43 and Cx26 in the heart as well as Cx26 and Cx32 in the liver of a rat model that aged naturally, rather than prematurely because of genetic mutations or age-related diseases.

The results obtained in the present study have demonstrated that these connexins decrease in rat cardiomyocytes and in rat hepatocytes as they age. This change was revealed only at protein level, as connexin-mRNAs remained unchanged during aging. Moreover, the aged rats showed an increase in body fat, whose subcutaneous layer tended to be higher.

Finally, how these changes could represent signs of physiological adaptation in successful aging was discussed.

连接蛋白是形成膜通道和半通道的跨膜蛋白。它们参与细胞通讯和组织稳态的维持。最近对人类和动物的研究表明，Cx43（研究最多的连接蛋白）的表达和分布会在衰老过程中发生变化。然而，目前对于其他连接蛋白参与心脏和肝脏衰老的研究还很薄弱。因此，本研究的目的是评估自然衰老而非因基因突变或年龄相关疾病而过早衰老的大鼠模型心脏中 Cx43 和 Cx26 以及肝脏中 Cx26 和 Cx32 的表达。

本研究获得的结果表明，随着年龄的增长，大鼠心肌细胞和大鼠肝细胞中的这些连接蛋白减少。这种变化仅在蛋白质水平上显现出来，因为连接蛋白 mRNA 在衰老过程中保持不变。此外，老年大鼠的体脂肪增加，皮下层往往更高。

最后，讨论了这些变化如何代表成功衰老的生理适应迹象。