Basso A, Rossolini G, Piantanelli L
Centre of Biochemistry, Gerontologic Research Department, INRCA, Ancona.
Boll Soc Ital Biol Sper. 1996 Mar-Apr;72(3-4):71-7.
Mouse hepatocytes undergo profound changes during aging, such as increased nuclear volume, occurrence of tetraploid nuclei and impaired DNA synthesis following in vivo adrenergic stimulation. These alterations have been found reversible by implanting a neonatal thymus into old animals. In the present paper we studied the optimal experimental conditions in order to investigate the mechanisms of such actions in vitro. Unfortunately, in fact, most of data in the field comes from experiments on rats. Thus, we examined DNA synthesis of hepatocytes from mice cultivated in presence of neonatal calf serum only, or after the addition of the beta-adrenergic agonist isoproterenol or the beta-adrenergic antagonist propranolol. DNA synthesis in hepatocytes from young Balb/c-nu mice shows a peak between 36 and 48 h even in the absence of any specific stimulation other than newborn calf serum. The addition of isoproterenol does not modify the DNA synthetic pattern, while propranolol causes a slight but statistically significant decrease in 3H-thymidine incorporation. Results are compared with those obtained from other authors in rats.
小鼠肝细胞在衰老过程中会发生深刻变化，如核体积增大、出现四倍体细胞核以及体内肾上腺素能刺激后DNA合成受损。通过将新生胸腺植入老年动物体内，已发现这些改变是可逆的。在本文中，我们研究了最佳实验条件，以便在体外研究此类作用的机制。事实上，不幸的是，该领域的大多数数据都来自对大鼠的实验。因此，我们检测了仅在新生牛血清存在下培养的小鼠肝细胞的DNA合成，或在添加β-肾上腺素能激动剂异丙肾上腺素或β-肾上腺素能拮抗剂普萘洛尔后的DNA合成。即使在没有除新生牛血清以外的任何特异性刺激的情况下，来自年轻Balb/c-nu小鼠的肝细胞中的DNA合成在36至48小时之间也会出现一个峰值。添加异丙肾上腺素不会改变DNA合成模式，而普萘洛尔会导致3H-胸腺嘧啶核苷掺入量略有下降，但具有统计学意义。将结果与其他作者在大鼠中获得的结果进行了比较。
