Cheng H, Bjerknes M
Department of Anatomy, University of Toronto, Ontario, Canada.
Anat Rec. 1990 Nov;228(3):262-6. doi: 10.1002/ar.1092280305.
Previous studies make it likely that the response of the intestinal epithelium as a whole to lactation is different from that observed in the crypt population alone. We confirm this difference by whole population cell kinetics measurements of jejunal and colonic epithelium in mice that have been suckling pups for various lengths of time. We found that the fraction of cells in S phase in jejunal epithelium was significantly increased after only 1 week of lactation, maintained this elevated level after 2 weeks of lactation, but returned to normal during the third week of lactation. The cell number density in jejunum was also significantly higher after 2 and 3 weeks of lactation before returning to normal by 4 weeks. In the colonic epithelium no changes were found in the distribution of cells in G1, S, and G2 + M phases. However, a significant increase in cell number density was observed after 2 weeks of lactation, followed by a sharp decrease to a level significantly below that of normal mice after 3 and 4 weeks of lactation. We conclude that the observed significant increase in the fraction of S phase in jejunal epithelium of lactating mice is probably due to a smaller relative expansion of the villus population when compared with the expansion of the crypt population. Our data also indicate that a number of cell kinetic parameters in the intestinal epithelium of lactating mice are changing throughout the period of lactation. Thus the intestinal epithelium is probably not in a steady state during lactation.
先前的研究表明，肠道上皮整体对哺乳的反应可能不同于仅在隐窝群体中观察到的反应。我们通过对不同哺乳时长的哺乳小鼠空肠和结肠上皮进行全群体细胞动力学测量，证实了这种差异。我们发现，仅哺乳1周后，空肠上皮中处于S期的细胞比例就显著增加，哺乳2周后维持在这一升高水平，但在哺乳第三周时恢复正常。哺乳2周和3周后，空肠中的细胞数密度也显著更高，到4周时恢复正常。在结肠上皮中，G1、S和G2 + M期细胞的分布没有变化。然而，哺乳2周后观察到细胞数密度显著增加，随后在哺乳3周和4周后急剧下降至显著低于正常小鼠的水平。我们得出结论，哺乳小鼠空肠上皮中观察到的S期比例显著增加，可能是由于与隐窝群体的扩张相比，绒毛群体的相对扩张较小。我们的数据还表明，哺乳小鼠肠道上皮的一些细胞动力学参数在整个哺乳期间都在变化。因此，哺乳期间肠道上皮可能不是处于稳态。
