Effects of TGF-β1 and IGF-1 on proliferation of human nucleus pulposus cells in medium with different serum concentrations

Rongfeng Zhang,Chao Zhang,Dike Ruan

doi:10.1186/1749-799x-1-9

Abstract

BackgroundThe low proliferative viability of human nucleus pulposus(NP) cells is considered as a cause of intervertebral discs degeneration. Growth factors, such as TGF-β1 and IGF-1, have been implicated in cell proliferation and matrix synthesis.ObjectiveTo investigate the dose-response and time-course effect of transforming growth factorβ1(TGF-β1) and insulin-like growth factor-1(IGF-1) on proliferation of NP cells.Study design3-(4,5-dimethylthiazolyl)-2,5-diphenyl-tetrazolium bromide (MTT) is reduced by dehydrogenase in mitochondria of live cells. The proliferative viability of cells corresponds to the amount of MTT reduced, which is measured with an enzyme-linked immunosorbent assay plate reader. In this study, we assessed dose- and time-dependent effects of NP cells to TGF-β1 and IGF-1 in medium with different serum concentrations by MTT assay.MethodsAfter release of informed consent, tissue samples of NP were obtained from anterior surgical procedures performed on five donors with idiopathic scoliosis. Isolated cells were cultured in F12 medium supplemented with 10% fetal bovine serum(FBS). Cells were seeded in 96-well plates at 1 × 103 cells/well. After synchronization, medium was replaced by F12 containing 1% or 10% FBS with either single or combination of TGF-β1 and IGF-1. Dose-response and time-course effect were examined by MTT assay.ResultsIn the presence of 1% FBS, the response to IGF-1 was less striking, whereas TGF-β1 had a remarkably stimulating effect on cell proliferation. In 10% FBS, both of the two growth factors had statistical significant mitogenic effects, especially TGF-β1. The dose-dependent effect of TGF and IGF on cell proliferation was found within different concentrations of each growth factor(TGF-β1 1–10 μg/L, IGF-1 10–100 μg/L). The time-course effect showed a significant elevation three days later.ConclusionTGF-β1 and IGF-1 were efficient to stimulate cell proliferation of human NP cells in vitro with a dose- and time-dependent manner. These results support the therapeutic potentials of the two growth factors in the treatment of disc degeneration.

Highlights

The low proliferative viability of human nucleus pulposus(NP) cells is considered as a cause of intervertebral discs degeneration
The dose-dependent effect of TGF and IGF on cell proliferation was found within different concentrations of each growth factor(TGFβ1 1–10 μg/L, IGF-1 10–100 μg/L)
TGF-β1 and IGF-1 were efficient to stimulate cell proliferation of human NP cells in vitro with a dose- and time-dependent manner. These results support the therapeutic potentials of the two growth factors in the treatment of disc degeneration

Summary

Introduction

The low proliferative viability of human nucleus pulposus(NP) cells is considered as a cause of intervertebral discs degeneration. Growth factors, such as TGF-β1 and IGF-1, have been implicated in cell proliferation and matrix synthesis. Intervertebral disc(IVD) degeneration and associated spinal disorders are a leading source of morbidity, resulting in substantial pain and increased health care costs. The exact mechanism of disc degeneration is not fully understood. The NP tissue is avascular, gelatinous and lies in the central of the IVD. A central feature of NP degeneration is loss of tissue cellularity. It has been suggested that apoptosis may be an important event that contributes to the death of cells in the disc[2]

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