Vandenburgh H H, Solerssi R, Shansky J, Adams J W, Henderson S A
Department of Pathology and Laboratory Medicine, Brown University School of Medicine, Providence, Rhode Island, USA.
Am J Physiol. 1996 May;270(5 Pt 1):C1284-92. doi: 10.1152/ajpcell.1996.270.5.C1284.
Adherent cultures of neonatal rat cardiomyocytes were subjected to progressive, unidirectional lengthening for 2-4 days in serum-containing medium. This mechanical stretch (25% increase in initial length each day) simulates the eccentric mechanical load placed on in vivo heart cells by increases in postnatal blood pressure and volume. The in vitro mechanical stimuli initiated a number of morphological alterations in the confluent cardiomyocyte population which were similar to those occurring during in vivo heart growth. These include cardiomyocyte organization into parallel arrays of rod-shaped cells, increased cardiomyocyte binucleation, and cardiomyocyte hypertrophy by longitudinal cell growth. Stretch stimulated DNA synthesis in the noncardiomyocyte population but not in the cardiomyocytes. Myosin heavy chain (MHC) content increased 62% over 4 days of stretch and included increased accumulation of both fetal beta-MHC and adult alpha-MHC isoforms. This new model of stretch-induced cardiomyocyte hypertrophy may assist in examining some of the complex mechanogenic growth processes that occur in the rapidly enlarging neonatal heart.
将新生大鼠心肌细胞的贴壁培养物在含血清培养基中进行2至4天的渐进性单向拉长。这种机械拉伸（每天初始长度增加25%）模拟了出生后血压和血容量增加给体内心脏细胞带来的离心机械负荷。体外机械刺激在融合的心肌细胞群体中引发了许多形态学改变，这些改变与体内心脏生长过程中发生的改变相似。这些改变包括心肌细胞排列成平行的杆状细胞阵列、心肌细胞双核化增加以及通过纵向细胞生长导致的心肌细胞肥大。拉伸刺激了非心肌细胞群体中的DNA合成，但未刺激心肌细胞中的DNA合成。在拉伸的4天内，肌球蛋白重链（MHC）含量增加了62%，包括胎儿β-MHC和成人α-MHC同工型的积累增加。这种拉伸诱导的心肌细胞肥大新模型可能有助于研究快速生长的新生心脏中发生的一些复杂的机械生长过程。
