| Abstract: | 此研究，第一次採先天性中風傾向高血壓母鼠及同時餵食1%食鹽之母鼠為對象，分別比較其出生幼鼠 ( 1至20天 ) 與正常幼鼠心肌的發育差異。先天性中風傾向幼鼠以SP表示，而餵鹽產生之幼鼠以SF表示。實驗中測量全量之心肌去氧核糖核酸 ( DNA )、核糖核酸 ( RNA ) 及蛋白質代表生長速率，並以正常之WKY鼠作為對照。發現出生後第一天，SP及SF幼鼠之心肌重量分別比正常幼鼠高35%及15%。出生3-10天，則分別增加3倍及2倍。然而至出生地20天，則SF與WKY重量相似，但卻比SP少了15%。且在20天內此三組幼鼠之心肌相對含水重並無差異。三組幼鼠之心肌DNA在前1-5天一直增加，且SF及SP明顯大於WKY，但至第20天則三組DNA含量均相同。但僅僅SP幼鼠在出生第1天，RNA和蛋白質明顯增加，至第20天則三組動物均無差異。顯然SP及SF幼鼠之心肌早期發育模式與WKY不同。為了克服基因性的缺陷，SP及SF幼鼠之心肌在出生初期及有了心肌肥大的適應性現象。但SP幼鼠早期心肌生長的適應性，卻可因母鼠食鹽的過度攝取而減弱。
This study, for the first time, investigates the growth of the heart during the early postnatal period (1-20 days) in pups to stroke-prone spontaneously SP and SF, respectively. Growth rate of the heart was measured by weight as well as by concentrations of total DNA, RNA, and protein. Measurements of growth of the heart in pups born to normotensive WKY rats served as controls. At day 1postnatal, the heart weights of SP and SF pups were larger by 35% and 15% respectively, than that of WKY rats. Between 3 and 10 days, heart weight increases about 3-fold in SF and only 2-fold in SP and WKY. However, by 20 days, the heart weight of SF is the same as that of WKY and 15% less than SP. Relative water content of the hearts of the three strains did not differ at any time during the 20 days postnatal period. The hearts of the three strains showed an increased DNA concentration for up to 5 days, though the concentrations in SF and SP were significantly higher than those in WKY rats. By 20 days, however, all three strains had the same the DNA concentration. At day 1 postnatal, only the hearts of FP pups had increased concentrations of RNA and protein. At 20 days, the RNA and protein concentrations were the same in all three strains. In summary, growth patterns of the hearts in SF and SP pups differ from those of WKY rats especially during the early postnatal period. Furthermore, the course of growth of the heart in SP pups in the early period after birth can be modified environmentally, i.e., by excess salt intake by the parent animals. |
