A Mouse Model of Lumbar Spine Instability

Summary

We developed a lumbar intervertebral disc degeneration mouse model by resection of L₃–L₅ spinous processes along with supra- and inter-spinous ligaments and detachment of paraspinous muscles.

Abstract

Intervertebral disc degeneration (IDD) is a common pathological change leading to low back pain. Appropriate animal models are desired for understanding the pathological processes and evaluating new drugs. Here, we introduced a surgically induced lumbar spine instability (LSI) mouse model that develops IDD starting from 1 week post operation. In detail, the mouse under anesthesia was operated by low back skin incision, L₃–L₅ spinous processes exposure, detachment of paraspinous muscles, resection of processes and ligaments, and skin closure. L₄–L₅ IVDs were chosen for the observation. The LSI model develops lumbar IDD by porosity and hypertrophy in endplates at an early stage, decrease in intervertebral disc volume, shrinkage in nucleus pulposus at an intermediate stage, and bone loss in lumbar vertebrae (L₅) at a later stage. The LSI mouse model has the advantages of strong operability, no requirement of special equipment, reproducibility, inexpensive, and relatively short period of IDD development. However, LSI operation is still a trauma that causes inflammation within the first week post operation. Thus, this animal model is suitable for study of lumbar IDD.

Introduction

Intervertebral disc degeneration (IDD) is commonly seen in aging and even young people caused by many factors¹. Surgery for patients who suffer from IDD, causing low back pain and impaired movement, is usually performed at a later stage or in severe cases and has potential risks such as nonunion or infection². Ideal non-operative treatment requires comprehensive understanding of the IDD mechanism. The IDD animal model serves as a crucial tool for studies of IDD mechanism and evaluation of IDD treatment.

Larger animals have been chosen for IDD models such as primates, sheep, goats, dogs, and ra....

Protocol

The investigations described conform to the Guidelines for the Care and Use of Laboratory Animals of the National Institutes of Health and were approved by Shanghai University of Traditional Chinese Medicine Animal Care and Use Committee. All surgical manipulations were performed under deep anesthesia and the animals did not experience pain at any stage during the procedure.

1. Pre-operation preparation

1. Instrument sterilization: Steam-sterilize surgical instruments in an autoclave (121 °C for 15 min) prior to the surgery. Pack instruments in a metal container and maintain them until they are used in the surgery.
2. S....

Results

The LSI mouse model is applied in the studies of IDD mechanism, IDD treatment, endplate (EP) degeneration such as sclerosis, and sensory innervation in EP^20,21,22,23. The LSI mouse develops IDD and EP degenerative changes, as identified, by decreased IVD volume and height, increased EP volume, and increased IVD and EP scores.

The dissected and fixed lower thoracic an.......

Discussion

We developed the lumbar spine instability mouse model based on the cervical spondylosis mouse model in which the posterior paravertebral muscles from the vertebrae were detached and the spinous processes along with the supraspinous and interspinous ligaments were resected²⁵. We performed a similar operation onto the lumbar spine, which has more prominent spinous processes. The LSI mouse model developed similar IDD in the lumbar spine.

The advantages of the LSI model inc.......

Materials

List of materials used in this article

Name	Company	Catalog Number	Comments
Chlortetracycline Hydrochloride Eye Ointment	Shanghai General Pharmaceutical Co., Ltd.	H31021931	Prevent eye dry, Prevent wound infection
C57BL/6J male mice	Tian-jiang Pharmaceuticals Company (Jiangsu, CN)	SCXK2018-0004	Animal model
Disposable medical towel	Henan Huayu Medical Devices Co., Ltd.	20160090	Platform for surgical operation
Inhalant anesthesia equipment	MIDMARK	Matrx 3000	Anesthesia
Isoflurane	Shenzhen RWD Life Technology Co., Ltd.	1903715	Anesthesia
Lidocaine hydrochloride	Shandong Hualu Pharmaceutical Co., Ltd.	H37022839	Pain relief
Medical suture needle	Shanghai Pudong Jinhuan Medical Products Co., Ltd.	20S0401J	Suture skin
Ophthalmic forceps	Shanghai Medical Devices (Group) Co., Ltd. Surgical Instruments Factory	JD1050	Clip the skin
Ophthalmic scissors(10cm)	Shanghai Medical Devices (Group) Co., Ltd. Surgical Instruments Factory	Y00030	Skin incision
silk braided	Shanghai Pudong Jinhuan Medical Products Co., Ltd.	11V0820	Suture skin
Small animal trimmer	Shanghai Feike Electric Co., Ltd.	FC5910	Hair removal
Sterile surgical blades(12#)	Shanghai Pudong Jinhuan Medical Products Co., Ltd.	35T0707	Muscle incision
Veet hair removal cream	RECKITT BENCKISER (India) Ltd	NA	Hair removal
Venus shears	Mingren medical equipment	Length:12.5cm	Clip the muscle and spinous process