Precision-cut liver slices (PCLS) refer to thin sections of liver tissue obtained through a specialised cutting technique done with Compresstome vibratomes.^[1] These slices are utilised to study drug metabolism, toxicity, and other aspects of liver function in a controlled laboratory setting.^[2][3]

Liver tissue is prepared for cutting into PCLS with the Compresstome vibratome.

PCLS provide a robust ex vivo model; they maintain the liver's complex structure. PCLS are used for investigating mechanisms of liver injury and identifying therapeutic targets.^[4][5][6]

History

Carlos Krumdieck introduced the Krumdieck tissue slicer for the first time in 1980.^[7] This allowed rapid production of tissue slices. In 1985, PCLS were first introduced by Smith et al. as an in vitro model for toxicity testing. Initially the primary objectives of PCLS were metabolic studies and toxicity testing.^[7] The focus of PCLS experiments shifted towards studies of chronic liver disease, such as fibrosis from 2005 onwards. The production of liver and intestinal tissue slices from humans and rats was described and published by de Graaf et al. in 2010. This technique is currently the standard procedure used by researchers for PCLS cultures.^[7]

Basic preparation

Creating PCLS is a meticulous process that involves several essential steps. The use of Compresstome vibratomes is crucial in ensuring the production of precise and high-quality slices for research purposes.

Liver tissue (PCLS) made and stained for immunofluorescence imaging.

Use of vibratomes

Vibratome by Precisionary Instruments

The basic steps involved in preparing PCLS using Compresstome vibratomes include:^[8]

Tissue selection

Start by carefully selecting liver tissue from the desired species, such as rodents or humans, ensuring the tissue is of high quality and health.

Tissue embedding

To facilitate slicing and maintain tissue structure, the liver tissue is typically embedded in a suitable medium, such as agarose or gelatin, into the specimen holder of the Compresstome vibratome.

Slicing process

The vibratome operates by oscillating a blade vertically at high frequencies while the tissue is submerged in a cutting solution. This mechanical oscillation creates thin and precise slices of tissue. Researchers can adjust cutting parameters, such as slice thickness, to meet specific experimental requirements. Typically, PCLS have thicknesses ranging from 200–500µm.

Post-processing

Depending on the research objectives, PCLS may undergo additional steps such as washing, culturing, or treatment with substances of interest, such as drugs or stimuli.

Advantages of PCLS

There are several benefits of using PCLS in medication development and research. They offer more physiologically possible models compared to standard cell culture. More accurate evaluations of drug metabolism, toxicity, and overall liver function are made possible by this approach, which maintains tissue architecture, cell-cell connections, and metabolic processes.^[10] PCLS help researchers to understand medication processes and potential side effects by allowing them to examine how drugs affect particular types of liver cells. Slice thickness uniformity improves accuracy and is a useful tool for in vitro research that closely resembles in vivo settings.^[4]

Limitations of PCLS

PCLS have several limitations, such as only lasting a few hours.^[11] This may limit the duration of the research and make it difficult to see the long-term effects of some drugs. Furthermore, slicing and preparing the slices may cause stress reactions, which might affect the results of the experiment. It might be difficult, but maintaining physiological oxygen levels and nutrition supplies during the experiment is essential. These drawbacks highlight the necessity of cautious experimental planning and interpretation when using PCLS in studies.^[12]

References