Acquired structural kyphoscoliosis in a captive adult female rhesus macaque (Macaca mulatta).

A female, wild-caught, rhesus macaque (Macaca mulatta), in captivity for 23 years and estimated to be older than 26 years, had an 8-year history of progressive spinal curvature. Scoliosis was initially noted 1 year after a therapeutic bilateral ovariectomy to treat endometriosis. Eight years after the initial diagnosis, the curvature had progressed to a structural (nonflexible), lumbar scoliosis with a curvature to the left and a structural thoracolumbar kyphosis. The spinal curvature was characterized radiographically by a severe, major lumbar curve to the left with vertebral rotation and severe thoracolumbar kyphosis. The Cobb method of measurement identified a major left lumbar curve of 80 degrees. When the animal's condition deteriorated, the animal was euthanized, and a necropsy with postmortem radiographic and microscopic examination was performed. Radiographically and grossly, multiple intervertebral disc spaces were narrowed along the entire spine with ventral bridging intervertebral spondylosis of the lumbar spine. Radiographically, vertebral bodies appeared to be less radiodense and multiple features of degenerative disc disease were present. No clinical evidence of concurrent neuromuscular or mesenchymal disease was noted, and development of lesions after bilateral ovariectomy suggested the kyphoscoliosis was secondary to osteopenia that developed as the result of a surgically induced estrogen deficiency.

In vivo micro computed tomography of subchondral bone in the rat after intra-articular administration of monosodium iodoacetate.

Osteoarthritis (OA) is a degenerative disease that is characterized by joint discomfort, loss of articular cartilage, and changes to the subchondral bone. Studies to elucidate the pathophysiology of OA have been hampered by the lack of a rapid, reproducible animal model that mimics the structural changes associated with the disease. A single intra-articular injection of mono-iodoacetate (MIA), an inhibitor of glycolysis, into the femorotibial joint of rodents promotes loss of articular cartilage similar to that noted in human OA. The purpose of the present study was to determine whether in vivo three-dimensional micro computed tomography (microCT) was of use for detecting progressive changes over time to the subchondral bone (femorotibial joint) of Wistar rats treated with a single intra-articular injection of MIA. MIA-treated right knee joints and left contralateral control knee joints were imaged in vivo at 0, 1, 7, 14, 28, and 56 days postinjection by using microCT. Analysis of 50- and 100- micro m resolution images demonstrated that changes to the subchondral bone, as determined by visual and bone mineral density analysis, are apparent by day 14 post-MIA. By day 28, there were marked changes to lateral aspect of the medial tibial plateaus of the subchondral bone in MIA-treated joints. These changes were progressive through day 56. It was concluded that intra-articular injection of MIA induces progressive changes to subchondral bone that can be assessed using in vivo microCT imaging. In light of these data, in vivo microCT imaging represents a valuable tool for investigating bone remolding and has the potential to be used for routine, high-throughput analysis and screening of investigation therapeutics.

Clinical considerations in rodent bioimaging.

Imaging modalities such as micro-computed tomography (micro-CT), micro-positron emission tomography (micro-PET), high-resolution magnetic resonance imaging (MRI), optical imaging, and high-resolution ultrasound are rapidly becoming invaluable research tools. These advanced imaging technologies are now commonly used to investigate rodent biology, metabolism, pharmacokinetics, and disease in vivo. Choosing an appropriate anesthetic regimen as well as monitoring and supporting the animal's physiologic balance is key to obtaining images that truly represent the biologic process or disease state of interest. However, there are many challenges in rodent bioimaging such as limited animal access, small sample volumes, anesthetic complications, strain and gender variability, and the introduction of image artifacts. Because each imaging study presents unique challenges, a thorough understanding of the imaging modality used, the animal's health status, and the research data desired is required. This article addresses these issues along with other common laboratory animal clinical considerations such as biosecurity and radiation safety in in vivo rodent bioimaging.