ABSTRACT. We investigated the epidemiological characteristics of intervertebral disc herniation (IVDH) in Japan in a large population using a retrospective study. The sample population was dogs (n=297) with IVDH in Japan. Medical records were reviewed for breed, sex, age, affected interspace and neurological severity. The dogs were comprised of 132 cases of cervical IVDH (C-IVDH) and 165 cases of thoracolumbar IVDH (TL-IVDH). In Japan, the Dachshund, Beagle and Shih Tzu tended to suffer from both C-IVDH and TL-IVDH. The Shiba Inu, a characteristic Japanese dog breed, suffered from both C-IVDH and TL-IVDH, although there was little data relating to the whole breed. Male dogs tended to suffer from C-IVDH and TL-IVDH at a rate almost twice that of females in Japan. Among the three predominant dog breeds, the Dachshund, Beagle and Shih Tzu, the Dachshund tended to suffer from both C-IVDH and TL-IVDH at an earlier age than the Beagle, and the Beagle tended to suffer from both C-IVDH and TL-IVDH earlier than the Shih Tzu. Among the three predominant breeds, the Shih Tzu, in particular, tended to suffer from both C-IVDH and TL-IVDH at multiple sites. Our data from Japan were in partial agreement with previous data from the U.S.A., and epidemiological characteristics of IVDH peculiar to Japan were also identified. KEY WORDS: age at admission, canine, chondrodystrophoid dog, epidemiological study, intervertebral disc disease.J. Vet. Med. Sci. 70 (7): [701][702][703][704][705][706] 2008 Cervical and thoracolumbar intervertebral disc herniation (IVDH) is a common cause of spinal cord dysfunction in dogs seen in small animal practice [1]. Herniation of the disc causes various grades of myelopathy, including pain, paresis and sometimes permanent paralysis. The epidemiology of IVDH in dogs has been widely studied in the U.S.A., with studies investigating a variety of epidemiological factors including breed, sex, age, location of affected interspace, the time between onset of clinical signs to having a medical examination and the severity of the clinical signs. In particular, many reports have suggested that chondrodystrophoid dog breeds tend to suffer from IVDH, with a mean age at admission that differs significantly from other breeds [6,12,13,18,22]. Epidemiological data provide clinical veterinarians with an advantage prior to diagnosis or medical treatment of IVDH. However, in Japan, the epidemiological characteristics of IVDH in dogs have not been studied sufficiently [20]. Differences in the epidemiological characteristics of IVDH in dogs between the U.S.A. and Japan might exist because the characteristics of the disease may depend in part on the canine population or the living environment of the country. To establish whether this is the case, it is necessary to examine original Japanese epidemiological data for IVDH in dogs. Therefore, we investigated the epidemiological characteristics of IVDH in Japan in a large population using a retrospective study, and in particular, evaluated the association between specific br...

Results indicated that RUNX2 mRNA and protein expression in the NP are enhanced in aging intervertebral disks in dogs.

ABSTRACT. The causes of early degeneration and calcification of the nucleus pulposus in the chondrodystrophoid dog are poorly understood, and the underlying molecular mechanism of this process has not yet been clearly defined. Type X collagen is one of the key molecules in endochondral bone growth and development, especially matrix calcification. The relationship between type X collagen and disc degeneration and calcification in chondrodystrophoid dogs has not yet been studied. We analyzed the expression of type X collagen in degeneration and calcification of the intervertebral disc in chondrodystrophoid dogs, using type X collagen immunohistochemistry. Control intervertebral discs were collected from five dogs (4 female, 1 male, average age 1.3 years, beagle breed). Degenerated intervertebral discs were surgically removed from 11 canine patients with intervertebral disc extrusion (1 female, 10 male, average age 5.1 years, dachshund breed) in Nippon Veterinary and Animal Science University. All extruded disc samples showed hypertrophic changes and clustering of cells, typical features observed in the degenerated nucleus pulposus. The relative expression of type X collagen in the degenerated nucleus pulposus (84.3 ± 11.0%) was significantly increased compared to the control nucleus pulposus (5.4 ± 5.4%). Our findings suggest that type X collagen might contribute to the development of degeneration or calcification in the nucleus pulposus of the chondrodystrophoid dog. KEY WORDS: chondrodystrophoid dog, degenerated disc, type X collagen.J. Vet. Med. Sci. 70(1): 37-42, 2008 Intervertebral disc extrusion (IVDE) is a common cause of spinal cord dysfunction in dogs [4,25]. Disc extrusion results from rupture of the outer fibrous layers and subsequent extrusion of the nucleus pulposus into the vertebral canal. Extrusion of the nucleus pulposus may be caused by impact injury, mechanical compression of the spinal cord or both, and causes pain and paralysis which may be permanent. IVDE occurs more often in chondrodystrophoid dogs when compared with the general population [2, 5-7, 9, 11, 13]. The peak incidence of clinical disease occurs at a much earlier age in chondrodystrophoid breeds [5,9]. The intervertebral disc of a newborn chondrodystrophoid puppy macroscopically appears glistening and gelatinous, and is similar to a disc from a non-chondrodystrophoid puppy [11]. However, changes in the nucleus pulposus occur earlier than in other breeds of dog, and by one year of age the gelatinous nucleus has been replaced almost entirely by cartilaginous tissue. With increasing age, degenerative changes and frequently matrix calcification can be observed in the nucleus pulposus. It is considered that the early intervertebral disc degeneration in chondrodystrophoid dogs is related to the high incidence of IVDE [11]. The causes of early degeneration and calcification of the nucleus pulposus in the chondrodystrophoid dog are poorly understood, and the underlying molecular mechanism of this process has not yet been clearly define...