Objective: To investigate the proliferation of tissue-engineered cartilage cells stimulated by different intensities of compressive stress.
Methods: Human embryonic cartilage cells were seeded into type II collagen sponge scaffold. The cells of the pressure groups were stimulated by different compression rate (0-5%, 0-10%, and 0-20%) at a cyclical frequency of 0.1 Hz. The cells of the control group were cultured without pressure. Gross observation, histological section, MTT assay and flow cytometry were used to observe the morphology, cell number and distribution and detect the cell proliferation and cell cycle.
Results: Tissue-engineered cartilage cells in 0-10% group showed the largest size and greatest thickness with normal morphology. Tissue biopsies showed the largest number of cartilage cells with more uniform distribution, close alignment, more matrix secretion. The cartilage cell activity was significantly enhanced and the percentage of S phase cells significantly increased in the pressure group compared with those in the control group, and such changes were especially obvious in 0-10% group in which the S phase cells increased by 59.0% compared with that in the control group.
Conclusion: The proliferation of tissue-engineered cartilage cells is regulated by the cyclic stress intensity, and a pressure frequency of 0.1 Hz with compression rate of 0-10% can better promote the cell proliferation.