BACKGROUND: Macula adherens protein is found closely associated with congenital cardiac malformation and myocardial differentiation. OBJECTIVE: To investigate the expression characteristics of α-macula adherens protein in rat heart, as well as the property of age-dependant expression during myocardial growth. DESIGN: Randomized controlled, observational comparative study. SETTING: Department of Cell Biology of Xinxiang Medical College; Department of Bioengineering and Agricultural Economics of Puyang Vocational Technical School. MATERIALS: This study was conducted at the Morphological Laboratory of Xinxiang Medical College between January and June 2003. Totally 28 Wistar rats of clean grade were divided into infant group, youth group,middle-age group, and old-age group with 7 rats in each group. METHODS: All rats were anaesthetized and then cardiac tissues were cut into consecutive coronal slices of 5 μm thick. The expression of α-macula adherens protein in rat myocardium of infant, youth, middle-age and oldage groups was detected using IHC method. The positive cells displayed brownish yellow granules on the surface, cytoplasm and intercalated disc. Routine HE staining was performed on all specimens for structural comparison. MAIN OUTCOME MEASURES: The expression of α-macula adherens protein in rat myocardium of different groups. RESULTS: All the 28 rats entered the final results analysis. ① α-macula adherens protein was found to be expressed in myocardium in atrium, ventricle, papilla muscles and interventricular septum. ② In infant rats, the expression of α-macula adherens protein was mainly observed in intercalated disc at the end of myocardium, with less expression on cell surface and in cytoplasm; in contrast, α-macula adherens protein in young, middleaged and old rats was found to be typically expressed in intercalated disc at the end of myocardium. CONCLUSION: The expression of α-macula adherens protein displays age-dependant manner during rat myocardial development; moreover, the expression of α-macula adherens protein is found to be consistent with the development of intercalated disc.