PMID- 29770581 OWN - NLM STAT- MEDLINE DCOM- 20181015 LR - 20200225 IS - 1757-7861 (Electronic) IS - 1757-7853 (Print) IS - 1757-7853 (Linking) VI - 10 IP - 2 DP - 2018 May TI - Effect of Static Compression Loads on Intervertebral Disc: An in Vivo Bent Rat Tail Model. PG - 134-143 LID - 10.1111/os.12377 [doi] AB - OBJECTIVE: To evaluate how well different magnitudes of compression-induced degenerative changes using a bent rat tail model simulated human lumbar lordosis. It has been shown that compression plays an important role in intervertebral disc degeneration (IDD). METHODS: Sprague-Dawley rats (n = 25) were instrumented with a special compressive apparatus that was used to bend the intervertebral disc between the 8th and the 10th caudal vertebral bodies using two Kirschner wires inserted percutaneously into the middle of two tail vertebrae. Then, rats were divided into five different static compression loads (control, sham, 1.8 N, 4.5 N, and 7.2 N). The degeneration of the discs was evaluated by magnetic resonance imaging (MRI), histology, gene expression of anabolism and catabolism after 2 weeks. We used the signal characteristics of the disc in T2-weighted MRI to reflect the changes caused by degeneration as this is the most relevant and clinically recognized way to assess IDD. Pfirrmann classification was used to classify disc images. The tail discs from C(8-9) and C(9-10) with their two adjacent half vertebrae were carefully cut out and decalcified. Then the sections were paraffin-embedded and cut into 5-mum sections by histotome. Finally, they were stained with Safranin O-Fast Green and hematoxylin, and hematoxylin and eosin, respectively. Images were taken using a microscope and staining and compression-induced changes were assessed by a Masuda's grading scale. The relative expression levels of mRNA encoding rat anabolic genes and catabolic genes were evaluated by real-time reverse transcription (RT)-polymerase chain reaction (PCR). The mRNA expression fold change of the target gene was calculated using the 2(-DeltaDeltaCt) method in the loaded and unloaded disc. RESULTS: As the loading magnitude increased, static compression produced a significantly progressive decrease in nucleus intensity on T2-weighted MRI, a decrease of aggrecan and Type II collagen, an increase in Matrix metallopeptidase-3 (MMP-3) and MMP-13 expressions, and a histomorphological degeneration. The sham group had a score of 1.4 +/- 0.3, the 1.8 N group had a score of 2.4 +/- 0.3, the 4.5 N group had a score of 3.2 +/- 0.3, and the 7.2 N group had a score of 4.4 +/- 0.3, which was based on the Pfirrmann classification score, in which the control group had a score of 1. These results demonstrated that the sham group was not significantly different from the control group. Histological analysis showed that in the loaded disc, the size of the nucleus was reduced and that the annular layer was disorganized. Based on the Masuda grading scale, scores were as follows: for the control group, 3.8 +/- 0.35; sham, 4.2 +/- 0.35; 1.8 N, 5.4 +/- 0.35; 4.5 N, 7.6 +/- 0.35; and 7.2 N, 10 +/- 0.35. The gene expression was divided into the following: anabolic genes (aggrecan, collagen type1-alpha1, and collagen type2-alpha1) and catabolic genes (MMP-3 and MMP-13). Aggrecan and collagen type 2 were, respectively, downregulated from 0.42 +/- 0.04 to 0.21 +/- 0.04 and from 0.93 +/- 0.06 to 0.17 +/- 0.06 as the magnitude of compression increased, whereas collagen type 1 was significantly upregulated, from 2.49 +/- 0.19 to 4.40 +/- 0.19, when compared with the control group (from 1.8 to 7.2 N, P < 0.05). Catabolic genes MMP-3 and MMP-13 were significantly upregulated in all experimental groups (P < 0.05, MMP-3: from 1.46 +/- 0.18 to 3.44 +/- 0.18; MMP-13: from 1.19 +/- 0.12 to 2.82 +/- 0.13); however, MMP-13 exhibited no significant changes but tended to be upregulated when compared with the 1.8 N group with the 4.5 N group. CONCLUSIONS: Different stresses led to different processes of degenerative changes, the concave disc degenerating more severely as stress gradually increased. CI - (c) 2018 Chinese Orthopaedic Association and John Wiley & Sons Australia, Ltd. FAU - Xia, Wei AU - Xia W AD - Department of Orthopaedics, Orthopaedic Institute, The First Affiliated Hospital, Soochow University, Suzhou, China. FAU - Zhang, Lin-Lin AU - Zhang LL AD - Department of Orthopaedics, Orthopaedic Institute, The First Affiliated Hospital, Soochow University, Suzhou, China. FAU - Mo, Jun AU - Mo J AD - Department of Orthopaedics, Orthopaedic Institute, The First Affiliated Hospital, Soochow University, Suzhou, China. FAU - Zhang, Wen AU - Zhang W AD - Department of Orthopaedics, Orthopaedic Institute, The First Affiliated Hospital, Soochow University, Suzhou, China. FAU - Li, Hai-Tao AU - Li HT AD - Department of Orthopaedics, Orthopaedic Institute, The First Affiliated Hospital, Soochow University, Suzhou, China. FAU - Luo, Zong-Ping AU - Luo ZP AD - Department of Orthopaedics, Orthopaedic Institute, The First Affiliated Hospital, Soochow University, Suzhou, China. FAU - Yang, Hui-Lin AU - Yang HL AD - Department of Orthopaedics, Orthopaedic Institute, The First Affiliated Hospital, Soochow University, Suzhou, China. LA - eng PT - Journal Article DEP - 20180516 PL - Australia TA - Orthop Surg JT - Orthopaedic surgery JID - 101501666 RN - 0 (Aggrecans) RN - 0 (RNA, Messenger) RN - 9007-34-5 (Collagen) RN - EC 3.4.24.- (Matrix Metalloproteinase 13) RN - EC 3.4.24.- (Mmp13 protein, rat) RN - EC 3.4.24.17 (Matrix Metalloproteinase 3) SB - IM MH - Aggrecans/biosynthesis/genetics MH - Animals MH - Cauda Equina/diagnostic imaging/physiopathology MH - Collagen/biosynthesis/genetics MH - Disease Models, Animal MH - Gene Expression Regulation/physiology MH - Intervertebral Disc/diagnostic imaging/metabolism/*physiopathology MH - Intervertebral Disc Degeneration/diagnostic imaging/metabolism/pathology/*physiopathology MH - Magnetic Resonance Imaging MH - Matrix Metalloproteinase 13/biosynthesis/genetics MH - Matrix Metalloproteinase 3/biosynthesis/genetics MH - RNA, Messenger/genetics MH - Rats, Sprague-Dawley MH - Stress, Mechanical MH - Weight-Bearing PMC - PMC6594518 OTO - NOTNLM OT - Biomechanics OT - Disc degeneration OT - Intervertebral disc OT - Rat model OT - Spine EDAT- 2018/05/18 06:00 MHDA- 2018/10/16 06:00 PMCR- 2018/05/16 CRDT- 2018/05/18 06:00 PHST- 2016/11/12 00:00 [received] PHST- 2018/02/09 00:00 [accepted] PHST- 2018/05/18 06:00 [pubmed] PHST- 2018/10/16 06:00 [medline] PHST- 2018/05/18 06:00 [entrez] PHST- 2018/05/16 00:00 [pmc-release] AID - OS12377 [pii] AID - 10.1111/os.12377 [doi] PST - ppublish SO - Orthop Surg. 2018 May;10(2):134-143. doi: 10.1111/os.12377. Epub 2018 May 16.