MORPHOMETRIC-STEREOLOGIC ANALYSIS OF BROWN ADIPOCYTE DIFFERENTIATION IN ADULT MICE
MORPHOMETRIC-STEREOLOGIC ANALYSIS OF BROWN ADIPOCYTE DIFFERENTIATION IN ADULT MICE
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DOI：
10.1152/ajpcell.1992.262.4.c1018
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发表时间：
1992-04-01
影响因子：
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通讯作者：
BUKOWIECKI, LJ
中科院分区：
文献类型：
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作者：
GOGLIA, F;GELOEN, A;BUKOWIECKI, LJ
用形态计量体视学方法分析了成年小鼠间质干细胞向褐色脂肪细胞分化的过程。证实了先前的研究，确定了四个不同的发育阶段：1)间质细胞-> 2)原脂肪细胞（具有微小脂滴的间质细胞）-> 3)前脂肪细胞-> 4)成熟棕色脂肪细胞。棕色脂肪细胞前体细胞（间质细胞和原脂肪细胞）仅占棕色脂肪组织（BAT）总体积的一小部分（分别为1.7%和1.8%）。BAT体积主要由完全分化的多室细胞（65% vol/vol）、前脂肪细胞（12%）和毛细血管（10%）占据。原脂肪细胞向前脂肪细胞分化的特征是细胞体积增加了一倍（从800到1500 mu-m3），线粒体数量增加了5倍（221到1464），线粒体大小增加了8倍（从0.042到0.37 mu-m3），线粒体内膜表面密度增加了4倍（从8到35 mu-m2/mu-m3）。导致线粒体室的相对体积增大14倍（从2%到29%）。这种显著的线粒体增殖伴随着胞质脂滴数量和体积的增加。相比之下，前脂肪细胞向棕色脂肪细胞的分化主要表现为脂质室大小增加一倍；单液滴平均体积增加35倍，数量减少6 ~ 7倍。线粒体修饰轻微；内膜的表面密度只有轻微的增加。总之，棕色脂肪细胞分化的主要步骤是原脂肪细胞向前脂肪细胞的转化。其特点是线粒体大量增殖，嵴紧密堆积，与显著的脂肪生成有关，导致细胞体积显著扩大。
Brown adipocyte differentiation from interstitial stem cells was analyzed by morphometric-stereologic methods in adult mice. Confirming previous studies, four different stages of development were identified: 1) interstitial cells --> 2) protoadipocytes (interstitial cells with tiny lipid droplets) --> 3) preadipocytes --> 4) mature brown adipocytes. Brown adipocyte precursor cells (interstitial cells and protoadipocytes) occupied only a small fraction of total brown adipose tissue (BAT) volume (1.7 and 1.8%, respectively). Most of the BAT volume was occupied by fully differentiated multilocular cells (65% vol/vol), preadipocytes (12%), and blood capillaries (10%). The differentiation of protoadipocytes into preadipocytes was characterized by a doubling in the cellular volume (from 800 to 1,500-mu-m3) that was associated with a fivefold increase in the number of mitochondria (221 to 1,464), an eightfold augmentation in mitochondrial size (from 0.042 to 0.37-mu-m3), a fourfold increase in the surface density of the inner mitochondrial membrane (from 8 to 35-mu-m2/mu-m3), resulting in a 14-fold enlargement in the relative volume of the mitochondrial compartment (from 2 to 29%). This remarkable mitochondrial proliferation was accompanied by an increase in the number and volume of cytosolic lipid droplets. In contrast, the differentiation of preadipocytes into brown adipocytes was mainly characterized by a doubling in the size of the lipid compartment; the mean volume of single droplets increased 35 times but their number decreased 6-7 times. The mitochondrial modifications were minor; there was only a slight increase in the surface density of the inner membrane. In conclusion, the major step of brown adipocyte differentiation consists in the transformation of protoadipocytes into preadipocytes. It is characterized by a large proliferation of mitochondria with tightly packed cristae that is associated with a marked lipogenesis resulting in a significant expansion of the cellular volume.