Biochemical changes in the gastric mucosa after injury in young and aged rats.
Biochemical changes in the gastric mucosa after injury in young and aged rats.
复制标题
年轻和老年大鼠损伤后胃粘膜的生化变化。
DOI：
10.1016/0304-4165(89)90047-0
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发表时间：
1989
期刊：
影响因子：
--
通讯作者：
Luk,GD
中科院分区：
文献类型：
--
作者：
Majumdar,AP;Moshier,JA;Arlow,FL;Luk,GD
在幼年（4个月）和老年（24个月）的fisher -344雄性大鼠胃内灌胃2 M NaCl （1 ml/130 g b.w.）或等量水（对照）6小时后，检测胃粘膜胸苷激酶（TK）活性（增殖活性的指标）的变化。这些变化与胃黏膜c-mycgene的表达、酪氨酸激酶（Tyr-K）活性和酪氨酸特异性磷酸化蛋白有关。老龄大鼠胃黏膜基础TK活性（数据来自对照组）比幼鼠高75% （P< 0.001）。这伴随着c-mycgene的表达增加和Tyr-K活性增强67% （P< 0.001）。在两个年龄组中，2 M NaCl灌胃导致胃粘膜损伤（由病变指数证明）。然而，在老年大鼠中，发现病变指数比年轻大鼠高75%左右。在年轻大鼠中，粘膜损伤导致TK活性增加95%，而在老年大鼠中，与相应的对照相比，TK活性仅增加38%。年轻大鼠TK活性的2倍增加也与c-mycgene的表达增加有关。在幼龄大鼠中，高渗生理盐水导致Tyr-K活性增加90% (P< 0.001)，并显著刺激5种表观分子质量分别为170、120、100、55和43 kDa的粘膜蛋白的酪氨酸特异性磷酸化。另一方面，与对照组相比，老龄大鼠给予高压生理盐水后，胃粘膜中Tyr-K活性仅增加16% (P< 0.025)， c-mycgene表达和酪氨酸特异性磷酸化均未发生明显变化。我们的结论是，衰老增加了胃黏膜对损伤剂的易感性，并降低了其再生能力。我们还认为Tyr-K可能在决定这些事件中起作用。
Changes in gastric mucosal thymidine kinase (TK) activity (an indicator of proliferative activity) were examined in young (4 month) and aged (24 month) Fischer-344 male rats 6 h after intragastric administration of either 2 M NaCl (1 ml/130 g b.w.) or an equivalent volume of water (control). These changes were related to the expression of c-mycgene, tyrosine kinase (Tyr-K) activity and tyrosine-specific phosphorylation of proteins in the gastric mucosa. Basal gastric mucosal TK activity (data from the controls) in the aged rats was found to be 75% (P< 0.001) above the young animals. This was accompanied by increased expression of c-mycgene and a 67% (P< 0.001) enhancement in Tyr-K activity. Intragastric administration of 2 M NaCl resulted in gastric mucosal damage (as evidenced by lesions index) in both age groups. However, in aged rats, the lesions index was found to be about 75% higher than in their younger counterparts. In young rats, mucosal injury resulted in a 95% rise in TK activity, whereas in aged rats it was increased by only 38%, when compared with corresponding controls. This 2-fold rise in TK activity in young rats was also associated with increased expression of the c-mycgene. In young rats, administration of hypertonic saline caused a 90% (P< 0.001) increment in Tyr-K activity and significantly stimulated tyrosine-specific phosphorylation of five mucosal proteins with an apparent molecular mass of 170, 120, 100, 55 and 43 kDa. On the other hand, administration of hypertonic saline to the aged rats caused only a small 16% (P< 0.025) increase in Tyr-K activity, and produced no apparent change in either expression of c-mycgene or tyrosine-specific phosphorylation of any of the proteins in the gastric mucosa, when compared with the corresponding controls. We conclude that aging increases the susceptibility of the gastric mucosa to damaging agents and diminishes its regenerative capacity. We also suggest that Tyr-K may play a role in determining these events.