Open AccessIn vitro nucleus pulposus tissue model with physicochemical stresses
Author(s) -
Takeoka Yoshiki,
Kang James D.,
Mizuno Shuichi
Publication year - 2020
Publication title -
jor spine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.125
0ISSN - 2572-1143
DOI - 10.1002/jsp2.1105
Subject(s) - aggrecan , chemistry , hydrostatic pressure , osmotic concentration , anabolism , intervertebral disc , homeostasis , microbiology and biotechnology , biophysics , anatomy , biochemistry , biology , pathology , osteoarthritis , medicine , physics , alternative medicine , thermodynamics , articular cartilage
Intervertebral discs (IVDs) are exposed to changes in physicochemical stresses including hydrostatic and osmotic pressure via diurnal spinal motion. Homeostasis, degeneration, and regeneration in IVDs have been studied using in vitro, ex vivo, and animal models. However, incubation of nucleus pulposus (NP) cells in medium has limited capability to reproduce anabolic turnover and regeneration under physicochemical stresses. We developed a novel pressure/perfusion cell culture system and a semipermeable membrane pouch device for enclosing isolated NP cells for in vitro incubation under physicochemical stresses. We assessed the performance of this system to identify an appropriate stress loading regimen to promote gene expression and consistent accumulation of extracellular matrices by bovine caudal NP cells. Cyclic hydrostatic pressure (HP) for 4 days followed by constant HP for 3 days in high osmolality (HO; 450 mOsm/kg H 2 O) showed a trend towards upregulated aggrecan expression and dense accumulation of keratan sulfate without gaps by the NP cells. Furthermore, a repetitive regimen of cyclic HP for 2 days followed by constant HP for 1 day in HO (repeated twice) significantly upregulated gene expression of aggrecan ( P < .05) compared to no pressure and suppressed matrix metalloproteinase‐13 expression ( P < .05) at 6 days. Our culture system and pouches will be useful to reproduce physicochemical stresses in NP cells for simulating anabolic, catabolic, and homeostatic turnover under diurnal spinal motion.