Procedures for Morphologic Studies of Skeletal Muscle, Rat, Mouse, and Hamster

Procedures of Necropsy and Tissue Sampling

Necropsy is a major step of most studies using laboratory animals. During necropsy, tissue and organ noticeable grossly changes should be recorded and critical tissue samples may be stored for the subsequent evaluation. It is therefore important that the personnel in charge of this key experimental step to be adequately trained and aware of the study endpoints.

Tissue Sampling and Processing for Histopathology Evaluation

Histological procedures aim at providing good-quality sections that can be used for a light microscopic evaluation of tissue. These are applicable to identify either spontaneous or diseases-induced changes. Routinely, tissues are fixed with neutral formalin 10%, embedded in paraffin, and manually sectioned with a microtome to obtain 4-5 μm thick paraffin sections. Dewaxed sections are then stained with HE&S (hematoxylin-eosin and saffron) or can be used for other purposes (special stains, immunohistochemistry, in situ hybridization, etc.). During this processing, many steps and procedures are critical to ensure standard and interpretable sections. This chapter provides key recommendations to efficiently achieve this objective.

Necropsy and sampling procedures in rodents

Necropsy is a major step of most studies using laboratory animals. During necropsy, tissue and organ changes noticeable grossly can be recorded, and important tissue samples can be stored for subsequent evaluation. It is therefore important that the personnel in charge of this key experimentation step be adequately trained and aware of the study endpoints.

Histopathology procedures: from tissue sampling to histopathological evaluation

Histological procedures aim to provide good quality sections that can be used for a light microscopic evaluation of human or animal tissue changes in either spontaneous or induced diseases. Routinely, tissues are fixed with neutral formalin 10%, embedded in paraffin, and then manually sectioned with a microtome to obtain 4-5 μm-thick paraffin sections. Dewaxed sections are then stained with hematoxylin and eosin (H&E) or can be used for other purposes (special stains, immunohistochemistry, in situ hybridization, etc.). During this process, many steps and procedures are critical to ensure standard and interpretable sections. Key recomendations are given here to achieve this objective.

Revised guides for organ sampling and trimming in rats and mice--Part 3. A joint publication of the RITA and NACAD groups

This is the third part of a series of three articles on trimming instructions of rat and mouse protocol organs and tissues in regulatory type toxicity studies, covering the urinary, nervous, musculoskeletal, cardiovascular, and lymphoreticular systems. The article is based on the experience of the European RITA and American NACAD working groups and is an extended revision of trimming guides published in 1995 (BAHNEMANN et al.). The optimum localization for tissue preparation, the sample size, the direction of sectioning and the number of sections to be prepared is described organ by organ. These descriptions are illustrated for each organ by a schematic drawing and/or a macro-photograph showing the plane of section as well as a low magnification of the H&E stained slide demonstrating the optimum "end-product". The objectives of this work, as addressed in detail in the first part (Ruehl-Fehlert et al. 2003), are to standardize tissue sampling and trimming for comparison of historical data obtained from different studies and different laboratories, ensure the presence of all relevant target sites for histopathological evaluation and provide technical advice for preparatory techniques during necropsy, fixation and trimming (Crissman et al. 2004).