Target Deletion or Retention of Sections After Enzyme Digestion Monitored with Attenuation-of-Sound Images

Detecting tissue components is valuable in histology. Scanning acoustic microscopy (SAM) measures the attenuation of sound (AOS) through tissue sections to obtain histological images without the need for staining. AOS values are reduced as tissues break down. Here, we digested specific components using enzymes and followed the process with AOS imaging over time. Additionally, we applied specific dyes and antibodies to inhibit enzyme activity and preserve the target component within the section. Collagenase digested the bone to clearly visualise the internal structure. The target component showed a distinct decline in AOS values. Actinase digested the cervical artery except for amyloid deposits, which were detected by Congo red staining. Actinase-digested lymphoid cells remained horseradish peroxidase (HRP)-staining positive. Amylase digested some corpora amylacea (CA) in the brain, which became periodic acid-Schiff (PAS) staining negative and diminished in size upon electron microscopy observation. DNase digested and deleted cell nuclei, except for those stained with HRP or haematoxylin. Residual nuclear images of AOS matched those of light microscopy. Specific inhibition of enzymes preserved the target cells and materials. Our method offers a practical solution for intentionally deleting or retaining target components in a section. Furthermore, it provides a means to adjust and compare the degree of degradation using AOS values.