A Proinflammatory, Degenerative Organ Culture Model to Simulate Early-Stage Intervertebral Disc Disease.

Summary

This protocol presents a novel experimental model of proinflammatory, degenerative bovine organ culture to simulate early-stage intervertebral disc degeneration.

Abstract

Symptomatic intervertebral disc (IVD) degeneration (IDD) is a major socioeconomic burden and is characterized by inflammation and tissue degradation. Due to the lack of causative therapies, there is an urgent need for innovative experimental organ culture models to study the mechanisms involved in the progression of the disease, find therapeutic targets, and reduce the need for animal models. We here present a novel, three-dimensional organ culture model protocol mimicking the proinflammatory and catabolic microenvironment, which is present during IDD.

Initially, bovine caudal IVDs were dissected, cleaned, and cultured in the tissue culture medium. Dynamic physiologic or pathologic loading was applied in a custom-made bioreactor for 2 hours per day. IVDs were assigned to a control group (high glucose medium, physiological loading, phosphate-buffered saline injection) and a pathological group (low glucose medium, pathological loading, tumor necrosis factor-alpha injection) for four days. Gene expression analysis from collected nucleus pulposus cells of the IVDs and enzyme-linked immunosorbent assay of the conditioned organ culture media was performed.

Our data revealed a higher expression of inflammatory markers and reduced disc heights after loading in the pathological group compared to the control group. This protocol is reliable to simulate IVD inflammation and degeneration and can be further expanded to broaden its application scope.

Introduction

Low back pain (LBP) can affect individuals of all ages and is a leading cause for disability worldwide^1,2,3. The total cost associated with LBP exceeds $100 billion per year^4,5. Symptomatic intervertebral disc (IVD) degeneration (IDD), a condition characterized by inflammation and tissue degradation, is a major cause of LBP^6,7. Specifically, IDD is characterized by a gradually evolving breakdown of the IVD's extracellular matrix (ECM), induced and triggered by....

Protocol

Experiments were performed using bovine tails obtained from local abattoirs. The biological materials used in the current study are taken from the food chain and require no ethical approval in Swiss and European law.

1. Dissection of the bovine intervertebral disc

1. Rinse the whole tail thoroughly with tap water to remove dirt and hair on the surface.
   NOTE: With intact, distal ends, a maximum of 9 IVDs (coccygeal 1-9) per tail can be used for the experiments depending on the desired size of the IVDs. Considering the desired diameter between 15-20 mm, we used 12 bovine tails with 5 IVDs per tail for the experiments.

Results

Degenerative loading in low glucose medium combined with TNF-α injection caused a significant increase of the gene expression of proinflammatory markers interleukin 6 (IL-6) and interleukin 8 (IL-8) compared to the physiological control group in NP cells after 4 days of culture (Figure 2). In contrast, we did not observe significant changes for the proinflammatory genes interleukin 1β (IL-1β) and TNF-α in NP cells (data not shown). Furthermore, degenerative culture conditions did not alter t.......

Discussion

We here provided a detailed protocol to simulate degenerative and inflammatory IVDD. This protocol can be applied for detailed examinations of inflammatory pathways leading to the destructive effects on the disc. Moreover, the protocol can help to determine promising therapeutic targets involved in the progression of the disease.

We recently showed that human recombinant TNF-α could induce inflammation in both bovine and human NP cells²¹, which is in accordance wit.......

Materials

List of materials used in this article

Name	Company	Catalog Number	Comments
1-Bromo-3-chloropropane(BCP)	Sigma-Aldrich, St. Louis, USA	B9673
Ascorbate-2-phosphate	Sigma-Aldrich, St. Louis, USA	A8960
Band saw	Exakt Apparatebau, Norderstedt, Germany	model 30/833
Betadine	Munndipharma, Frankfurt, Germany
Bovine IL-8 Do.it-Yourself ELISA	Kingfisher Biotech, St. Paul, USA	DIY1028B-003
Corning ITS Premix	Corning Inc., New York, USA	354350
DMEM high glucose	Gibco by life technologies, Carlsbad, USA	10741574
DMEM low glucose	Gibco by life technologies, Carlsbad, USA	11564446
Ethanol for molecular biology	Sigma-Aldrich, St. Louis, USA	09-0851
Fetal Bovine Serum (FBS)	Gibco by life technologies, Carlsbad, USA	A4766801
Non-essential amino acid solution	Gibco by life technologies, Carlsbad, USA	11140050
Penicillin/Streptomycin(P/S)	gibco by life technologies, Carlsbad, USA	11548876
Phosphate Buffer Solution, tablet	Sigma-Aldrich, St. Louis, USA	P4417
Pronase	Sigma-Aldrich, St. Louis, USA	10165921001
Primocin	InvivoGen, Sandiego, USA	ant-pm-05
Pulsavac Jet Lavage System	Zimmer, IN,USA
TissueLyser II	Quiagen, Venlo, Netherlands	85300
Streptavidinn-HRP	Kingfisher Biotech, St. Paul, USA	AR0068-001
Superscript VILO	Invitrogen by life Technologies, Carlsbad, USA	10704274
cDNA Synthesis Kit	Applied Biosystems by life technologies	10400745
TaqMan Universal Master Mix	Applied Biosystems by life technologies
TNF-alpha, recombinant human protein	R&D systems, Minnesota, USA	210-TA-005
TRI Reagent	Molecular Research Center, Cincinnati, USA	TR 118
Tris-EDTA buffer solution	sigma-Aldrich, St. Louis, USA	93283
Gene bIL-6	Applied Biosystems by life technologies	Custom made probes	Primer fw (5′–3′) TTC CAA AAA TGG AGG AAA AGG A Primer rev (5′–3′) TCC AGA AGA CCA GCA GTG GTT Probe (5′FAM/3′TAMRA) CTT CCA ATC TGG GTT CAA TCA GGC GATT
Gene bIL8	Applied Biosystems by life technologies	Bt03211906_m1
Gene bTNF-alpha	Applied Biosystems by life technologies	Custom made probes	Primer fw (5′–3′) CCT CTT CTC AAG CCT CAA GTA ACA A Primer rev (5′–3′) GAG CTG CCC CGG AGA GTT Probe (5′FAM/3′TAMRA) ATG TCG GCT ACA ACG TGG GCT ACC G
GENE bIL1beta	Applied Biosystems by life technologies	Custom made probes	Primer fw (5′–3′) TTA CTA CAG TGA CGA GAA TGA GCT GTT Primer rev (5′–3′) GGT CCA GGT GTT GGA TGC A Probe (5′FAM/3′TAMRA) CTC TTC ATC TGT TTA GGG TCA TCA GCC TCA A
RPLP0	Applied Biosystems by life technologies	Bt03218086_m1