Study Design. Histological features of the intervertebral disc (IVD)-endplate interface were analyzed.
Objective. To define cartilaginous and bony vertebral endplate in commonly used laboratory animals and compare with that of the humans.
Summary of Background Data. Endplates are crucial for the IVD nutrient supply: the IVDs have limited blood supply; most nutrients diffuse through endplates to nourish the discs. Various animal models of IVD and endplate degeneration have been used to study the etiology and treatments of spinal disorders. However, because humans are biped, the spine mechanics differ significantly from other mammals. Translation of animal research findings requires a characterization and comparison of the vertebral endplate in the respective species. In this study, we compared the endplate structure of laboratory animal species at the age range commonly used for modeling spine degeneration with that of an adult human.
Methods. Mouse, rat, rabbit, goat, and human IVDs and the adjacent vertebral bodies were isolated from the lower lumbar spine. Tissues were stained with Alcian Blue, counterstained with hematoxylin and eosin.
Results. Structure of the vertebral endplate varied significantly between the adult animal species and that of the humans. Growth plates persisted in all adult animals studied, whereas the growth plate is absent in the adult humans. In the mice and rats, the cartilaginous endplates are in continuation with the growth plates, with only a small bony center. Rabbits and goats have a bony layer between cartilaginous endplate and the growth plate. The human endplate consist of a cartilaginous layer and the bony endplate.
Conclusion. Significant differences exist in histological features of the endplate across animal species and that of the humans. Consideration should be given when animal models are used to study IVD degeneration and surgical treatments.
Level of Evidence: 5
We aim to define endplate in commonly used laboratory animals and humans. Animal endplates differ significantly from that of the humans. The endplates of mice and rats are alike, and those of rabbits and goats share many similarities. Consideration should be given when animal models are used to study intervertebral disc (IVD) degeneration and treatments.
From the Departments of *Orthopedic Surgery
†Physical Medicine & Rehabilitation, and
‡Biochemistry, Rush University Medical Center, Chicago, IL
§Department of Physical Medicine and Rehabilitation, Perelman School of Medicine, University of Pennsylvania, and Philadelphia VA Medical Center, Philadelphia, PA
¶Department of Orthopedic Surgery, Second Hospital of Xiangya, Central South University, Hunan, P. R. China; and
‖Qujing No. 1 Hospital, Orthopedic Department, Yunnan Province, PR China.
Address correspondence and reprint requests to Yejia Zhang, MD, PhD, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104; E-mail: firstname.lastname@example.org
Acknowledgment date: June 10, 2013. First revision date: August 20, 2013. Acceptance date: August 27, 2013.
The manuscript submitted does not contain information about medical device(s)/drug(s).