Precision-cut kidney slices (PKS)

Background and rationale

Precision-cut kidney slices are thin sections of living kidney tissue that preserve the spatial organisation of glomeruli, vessels and tubules while remaining directly accessible to compounds added to the medium. Slices are cut from rodent or human kidney tissue on a vibrating microtome, allowed to restore their ATP levels in Williams' Medium E, and then cultured for up to 24 hours with the test compound present. Because the tissue stays metabolically active throughout, the model can be used to confirm that a compound reaches and acts on kidney tissue, to characterise direct nephrotoxicity, or to verify a mechanism of action before an animal study - a practical bridge between cell-based screens and animal studies.

Typical study design

• Kidney tissue pieces decapsulated and embedded in 3% agarose prewarmed at 40 °C
• Slices cut at 300 µm in ice-cold DPBS using a vibrating microtome (Compresstome VF310-0Z, Precisionary Instruments)
• Pre-incubation for 1 h at 37 °C in Williams' Medium E + GlutaMAX-I supplemented with 25 mM D-glucose and 1% Penn-Strep, under 80% O2 and 5% CO2, to restore slice ATP levels
• Culture for a further 24 h at 37 °C under 80% O2 and 5% CO2 on an orbital shaker at 80 RPM, with the test compound added to the medium
• Slices harvested in 10% formalin for histology and in RNAlater for RNA isolation; all conditions run as three technical replicates

Readouts

• Histology (HE, PAS) on formalin-fixed slices with blinded tubular injury scoring
• RNA isolation from RNAlater-preserved slices for qPCR and bulk RNA sequencing
• Tissue ATP content during recovery and culture as a measure of slice viability
• Target engagement and pathway markers by immunohistochemistry