The Comparative Pathology & Mouse Phenotyping Shared Resource (CPMPSR) provides expert, affordable, experimental pathology support to The Ohio State University Comprehensive Cancer Center members who utilize animal models to study human disease.
Anatomic Pathology Services
Examinations include gross and histopathologic analyses of various species of animal models with an emphasis on comprehensive phenotypic evaluations of genetically engineered mice and pre-clinical efficacy and toxicity studies. In addition, examinations of tissue biopsies, embryos and slide evaluations are also performed. Phenotypic Evaluation
Investigators typically submit for evaluation a minimum of three to five mice of each genotype, including the same number of age- and sex-matched controls. Controls are littermates exposed to the same environment and experimental conditions, not mice of the same background strain purchased from a commercial vendor.
After a brief ante mortem observation period, the mice are euthanized by carbon dioxide asphyxiation. They are then weighed, and blood is collected via percutaneous cardiac puncture for subsequent hematology and clinical chemistry.
Urine and other fluids can also be analyzed. Because of the small volumes obtained from mice, however, pooling of samples from mice of the same genotype, age and sex may be indicated.
Survey radiographs, including dorsal-ventral and lateral views, are taken with a Faxitron. Digital gross photographs are taken of any lesions in mutants and their lack thereof in controls.
A complete necropsy is performed. All organs are examined grossly, and the following organs are routinely weighed to the nearest milligram prior to fixation for determining organ-to-body weight ratios (percentage of body weight):
- liver with gall bladder
- kidneys (both)
- adrenals (both)
- ovaries/uterus or testes/epididymides
Other organ(s) can be weighed based on the pathologist's recommendation or investigator's request.
Tissues are trimmed according to a standardized protocol, fixed in 10 percent neutral buffered formalin, processed by routine methods, embedded in paraffin wax, and sectioned at 4 microns for standard H&E.
Unstained and frozen sections can also be made.
All bony tissues are decalcified prior to trimming. Tissues are evaluated histologically by a comparative pathologist board-certified by the American College of Veterinary Pathologists. Final reports include an interpretative summary and recommendations for ancillary analyses offered by the CPMPSR or other Shared Resources. Radiography
Extremely high resolution radiographic images of rodents as well as excised tissues are taken with a Faxitron to enhance morphologic evaluations of the skeletal system. For all other imaging modalities, investigative staff are referred to the Small Animal Imaging Shared Resource
Aperio Slide Scanning and Quantitative Image Analysis
Virtual microscopy provides innumerable benefits for teaching and research. Following digitization of histology slides with our Aperio ScanScope XT, free download of the Aperio ImageScope program (http://www.aperio.com/appcenter) allows users to view, capture and analyze the .svs file image. 20x and 40x resolution scanning of both regular 1”x3” and large 2”x3” glass slides is available. Automatic quantification of immunoreactivity can also be performed by our staff for a fee on whole slide images scanned at 40x magnification using Aperio's Image Analysis Toolbox with additional nuclear, cytoplasmic, membrane, and microvessel algorithms that also support pattern recognition and tissue microarrays.
Experienced histotechnologists provide complete histology services including tissue processing, embedding and sectioning of both paraffin-embedded and frozen animal tissues. Sectioning of methacrylate-embedded undecalcified bone can also be performed. Routine stains such as hematoxylin & eosin, and an extensive menu of both special histochemical and immunohistochemical stains optimized specifically for use on mouse tissues are available and continuously expanded. Such stains facilitate the identification of infectious agents, apoptotic and proliferating cells, angiogenesis, hematopoietic cell lineages, and more.
Customized tissue microarrays are prepared upon request.
Tissue samples can also be processed to grids for transmission electron microscopy. Investigative staff should then take the grids to the Microscopy Shared Resource
for utilization of their transmission electron microscope and acquisition of electron micrographs.
The CPMPSR participates in the quarterly HistoQuip quality assurance program for histochemistry and immunohistochemistry through the College of American Pathologists.Clinical Pathology Services
Services include hematology (complete blood counts with white blood cell differentials), serum biochemical panels, analysis of urine and other body fluids, and cytology.
Qualified laboratory professionals trained in veterinary laboratory techniques perform all tests. The laboratory staff is committed to research in improved diagnostics, reference range development and state-of-the art assays. New tests are continually added as experimental needs change. A network of reference laboratories is available for tests not performed in-house.
The CPMPSR participates in quarterly quality assurance testing for hematology and chemistry of laboratory animal samples in addition to the urinalysis and cytology modules through the Veterinary Laboratories Agency.
Investigators are provided hands-on training regarding tissue identification at the macroscopic and microscopic levels, necropsy technique and proper submission of biological specimens and tissues.
Experimental Design and Data Interpretation
Comparative pathologists actively participate in experimental design prior to submitting animals/tissues for pathologic evaluation as well as for subsequent studies and data interpretation. Recommendations are given for various ancillary tests (i.e. more specialized clinical pathology testing, electron microscopy, imaging, behavioral or physiological testing) provided by other Shared Resources or OSU research laboratories to further elucidate identified morphologic lesions or to rule out functional abnormalities when no morphologic lesions are found.
Routine contributions are also made to grant applications, manuscripts and oral/poster presentations in the form of digital photographs of macroscopic and microscopic lesions, details about methods and pathologic findings, and interpretation of results.