Scaglia L, Cahill C J, Finegood D T, Bonner-Weir S
Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts 02215, USA.
Endocrinology. 1997 Apr;138(4):1736-41. doi: 10.1210/endo.138.4.5069.
In rodents, shortly after birth a lack of increase in pancreatic weight and in islet mass have been reported during a time of overall body weight increase. To understand this regulation of the neonatal growth of the beta cell mass, we studied Sprague Dawley rats at 2, 9, 13, 17, 20, 24, and 31 days of age for beta cell replication, beta cell mass, and cell size and for the presence of cell apoptosis. beta cell mass was stable from 2-20 days (range: 0.91 +/- 0.2 to 1.33 +/- 0.23 mg) and increased thereafter. beta cell replication progressively decreased. Condensed apoptotic nuclei were identified and counted on paraffin sections using the fluorescent dye propidium iodide. Apoptotic beta cell nuclei were found at a basal rate (1.54 +/- 0.22%) at 2, 9, and again after 20 days of age. However, at 13 and 17 days, the incidence of apoptosis was significantly increased (3.64 +/- 0.45%). The decreased replication and the increased incidence of apoptosis in the beta cells strongly suggest a wave of neogenesis of beta cells to maintain the constant beta cell mass. These data show that the endocrine pancreas undergoes significant modification during neonatal life and that apoptosis is an important mechanism in this remodeling of the beta cell mass. Whether a selective deletion of some population of beta cells occurs is unclear, but a dysregulation of this remodeling process could have important effects on the pancreatic beta cell mass.
在啮齿动物中，有报道称出生后不久，在体重总体增加的时期，胰腺重量和胰岛质量并未增加。为了解β细胞团新生儿期生长的这种调节机制，我们研究了2、9、13、17、20、24和31日龄的斯普拉格·道利大鼠的β细胞复制、β细胞团、细胞大小以及细胞凋亡情况。β细胞团在2至20天内保持稳定（范围：0.91±0.2至1.33±0.23毫克），此后增加。β细胞复制逐渐减少。使用荧光染料碘化丙啶在石蜡切片上鉴定并计数浓缩的凋亡细胞核。在2日龄、9日龄以及20日龄之后，发现凋亡的β细胞核以基础速率（1.54±0.22%）存在。然而，在13日龄和17日龄时，凋亡发生率显著增加（3.64±0.45%）。β细胞复制减少和凋亡发生率增加强烈提示存在一波β细胞新生以维持恒定的β细胞团。这些数据表明，内分泌胰腺在新生儿期经历了显著变化，且凋亡是β细胞团重塑过程中的一个重要机制。尚不清楚是否发生了某些β细胞群体的选择性缺失，但这种重塑过程的失调可能对胰腺β细胞团产生重要影响。
