Table of Contents

Definition

Precision-cut tissue slices (PCTS) are viable, three-dimensional ex vivo explants sectioned from fresh animal or human tissue to a reproducible, well-defined thickness.¹ In metabolically active organs such as liver and lung, slices are cut at approximately 250 micrometres, which keeps every cell within the diffusion distance of oxygen and nutrients from the incubation medium.^{2 3} Because a slice retains the histoarchitecture of the parent organ—including its extracellular matrix, vascular and epithelial structures, and the full complement of resident parenchymal, stromal, and immune cells—it functions as a miniature model of the organ under study.^{1 4} Within this constraint, the tissue preserves the structural mechanics of the organ, including cell–cell and cell–matrix signalling, epithelial barrier geometry, and contractile elements such as airway smooth muscle, for days in culture.^{1 4}

Purpose

The primary value proposition of PCTS is that they combine the experimental control, replication, and throughput of in vitro systems with a physiological fidelity that monolayer cultures cannot reproduce, since the native architecture and multicellular context of the organ remain intact.^{1 5} A single organ yields dozens of uniform slices, so one animal or one donor supplies many independent exposure conditions, dose–response series, and time courses; this directly reduces animal use in line with the 3R principles and improves internal statistical control relative to between-animal designs.^{4 6} The decisive advantage over legacy models is human relevance: slices can be prepared from human donor tissue, including diseased tissue, so pharmacology and toxicology are measured in the target species rather than extrapolated from an animal surrogate.^{7 8} Human precision-cut kidney slices have, for example, been proposed as the basis of an animal-free preclinical drug screening platform.⁷ PCTS thereby replace part of exploratory animal experimentation and improve upon dissociated-cell systems, which lose tissue architecture and the resident stromal and immune context during isolation.^{1 5}

Methodology

Preparation begins with rapid procurement of fresh tissue, which is preserved in cold oxygenated buffer to minimize ischaemic injury.^{4 2} Cylindrical cores, typically 8 mm in diameter, are punched from the parenchyma and sectioned in a mechanical tissue slicer—the Krumdieck instrument, first described in 1980, or the Alabama Research and Development slicer—while the vibratome is increasingly used as an alternative cutting tool.^{4 2} For lung, the airspaces are inflated with low-melting-point agarose before sectioning to provide structural support and to maintain alveolar and airway geometry.³ Slices are transferred to multiwell plates in a defined, serum-supplemented medium—Williams’ Medium E is standard for liver—and incubated under gentle dynamic agitation to sustain oxygenation.^{4 2} Function is monitored with a standardized panel: ATP content and LDH release for viability, histomorphology for structural integrity, organ-specific outputs such as albumin and urea synthesis for liver slices, and gene and protein markers for pathway activation; exogenous stimuli such as TGF-β are applied to evoke fibrogenic responses in liver and intestinal slices.^{4 6 9} Human lung slices can additionally be cryopreserved and banked for on-demand use without loss of immune competence.¹⁰

Performance

In standard protocols, slices remain viable and metabolically competent for a 24 to 72 hour window that covers most acute exposure designs.^{4 2} With optimized culture, the functional window extends considerably: human lung slices can be maintained for up to two weeks³, cryopreserved human lung slices have been cultured for four weeks with preserved architecture and cellular viability¹⁰, and extended human liver slice cultures sustain regeneration-associated processes such as the ductular reaction over several days.¹¹ Slice dimensions are highly uniform within and between preparations when a calibrated slicer is used, which was the principal rationale for introducing the Krumdieck instrument and remains the basis of quantitative dose–response work.² The principal technical boundaries are the finite lifespan in culture, the inability to recruit non-resident immune cells such as circulating leukocytes, the diffusion-limited thickness that precludes organ-scale and vascular-level processes, donor-to-donor variability with human tissue, and residual batch-to-batch variation introduced during coring and cutting.^{2 3 10}

Applications

PCTS are applied across four principal domains. In toxicology and ADME research, liver and intestinal slices are used for drug metabolism, transporter induction, and hepatotoxicity testing; rifampicin induces P-glycoprotein expression, protein, and activity in human intestinal slices¹², and liver slices support drug-induced fibrosis and alcohol-related liver disease modelling^{6 8}. In respiratory research, lung slices support airway contraction pharmacology, asthma, COPD, fibrosis, and drug discovery programs, including the evaluation of therapeutic interventions in slices prepared from in vivo disease models.^{3 5 13} In renal research, kidney slices serve as an ex vivo screening platform for antifibrotic therapeutics and as the basis of an animal-free human drug screening platform.^{7 14} Beyond these domains, slices are used in infection and host–pathogen biology¹ and in studies of liver regeneration¹¹. Deployment remains at the research and preclinical-adoption stage: the model is established in academic laboratories and pharmaceutical research groups, where it informs internal decision-making, but no regulatory test guideline is yet built on it.^{3 5}

Variations

Precision-Cut Liver Slices — The most established subtype, used for hepatotoxicity, drug metabolism and transport, fibrosis, and alcohol-related liver disease modelling in human and rodent tissue.^{4 6 8}

Precision-Cut Lung Slices — Preserve airway, vascular, and alveolar architecture for respiratory pharmacology, asthma and COPD research, fibrosis studies, and cryopreserved on-demand test systems.^{3 10 13}

Precision-Cut Intestinal Slices — Retain full-thickness mucosal and muscularis architecture for ADME, transporter induction, and fibrogenesis studies in human tissue.^{12 9}

Precision-Cut Kidney Slices — Support nephrotoxicity testing, antifibrotic drug screening, and epithelial integrity assessment in human renal tissue.^{7 14 15}