To identify (by naked eye or with a dissecting microscope) malformations or pathomorphological lesions that characterize the mouse. Tissues collected for subsequent examination require appropriate handling and preservation to prevent tissue deterioration. The service includes:
mice: six experimental mice (three males and three females) and six age-matched
controls (three males and three females) are a minimum required.
Age: Analyses are performed at about 4 months of age. However, as mutations/treatments may affect the propensity to develop age-related diseases, it may be necessary to investigate old (i.e. over 12 months of age) and eventually senescent (i.e. over 24 months of age) subjects to discover pathological phenotypes.
All listed organs are dissected following a systematic necropsy procedure or, alternatively, collected according to gene expression patterns or to clinical findings. If the effect of the mutation is unknown, a systematic necropsy is recommended for each mouse.
|Liver, pancreas (exocrine), salivary glands
|Esophagus, stomach, duodenum, ileum, colon
|Central nervous system
|Eye and adnexia, tongue
|Pituitary, thyroid, and adrenal glands, pancreas (endocrine)
|Immune and haematopoietic system
|Thymus, spleen, lymph nodes, bone marrow
|Urinary bladder, kidney
|Male reproductive system
|Testis, epididymis, prostate, seminal vesicles, preputial glands
|Female reproductive system
|Ovaries, oviducts, uterus, vagina
|Striated muscle, knee joint
|Supporting and connective tissues
|White and brown adipose tissue
|Integumentary system and mammary gland
|Skin and appendages, mammary gland
Standard histopathological evaluation is performed on 10 % formalin fixed paraffin embedded 5µm-thick and hematoxylin & eosin stained sections (see histological techniques). All lesions are scored to enrich analyses with basic statistics. This allows to propose more comprehensive reports.
Special histopathological evaluation can also be performed: Detection of atherosclerotic lesions using en face staining of aorta. Whole aortas are dissected under stereomicroscopes and stained with Sudan IV, the lesions are subsequently quantified.
Automated research microscope equipped with a digital camera.
Slide scanner Nanozoomer 2.0 HT (Hamamatsu Photonics K.K., Hamamatsu City, Japan).
Different fixation methods can be used according the needs (see histological techniques)
To allow "meaningful" scientific interpretation of histopathological data through analysis of large cohorts of mice. On a practical level, 24 mice per age group (i.e., number used in systematic clinical tests) is recommended. However, as it takes several hours of technician time to collect, process and stain the tissues of a single mouse, economical aspects must be taken into account. These time considerations highlight the need for a phenotyping strategy.