Related Experiment Video
Updated: Jul 13, 2026
Investigation of Macrophage Polarization Using Bone Marrow Derived Macrophages
Published on: June 23, 2013
Significance of PAM histochemical reaction in delineating macrophages
Yuji Shinya1, Kazuya Hamada, P D Gupta
1Department of Physiological Science Anatomy 2, Faculty of Medicine, University of the Ryukyus, 207 Uehara, Nishihara, Okinawa, 903-0215 Japan.
Abstract:
Periodic acid methenamine silver staining has been used for proof of the existence of carbohydrates in both paraffin and resin embedded tissues. The staining was applied to delineate macrophages that have been well known as cells of mononuclear phagocyte system by stainable nature for lysosomes, and it is found to be useful method for detection of macrophage. Fetal macrophage, which is often observed in placental villi, is called the highly vacuolated cell. Vacuoles in the cytoplasm seem to be empty with light microscopic staining, but it is clarified that they contain a full amount of carbohydrate. The present result leads us to the necessity of reconsidering the functional aspect of fetal macrophage.
Insights
Periodic acid methenamine silver staining reveals carbohydrates in fetal macrophages within placental villi. This finding suggests a crucial, previously underestimated role for these cells in carbohydrate metabolism.
Area of Science:
- Histology
- Cell Biology
- Biochemistry
Background:
- Periodic acid methenamine silver staining detects carbohydrates in tissues.
- Macrophages, part of the mononuclear phagocyte system, are identifiable by lysosomal staining.
- Fetal macrophages in placental villi are characterized by cytoplasmic vacuoles.
Purpose of the Study:
- To evaluate the utility of periodic acid methenamine silver staining for macrophage detection.
- To investigate the composition of vacuoles in fetal macrophages.
- To reconsider the functional significance of fetal macrophages.
Main Methods:
- Application of periodic acid methenamine silver staining to paraffin and resin-embedded tissues.
- Microscopic examination of stained tissues to identify macrophages and analyze vacuole content.
Main Results:
- Periodic acid methenamine silver staining effectively delineates macrophages.
- Vacuoles in fetal macrophages, appearing empty under light microscopy, are rich in carbohydrates.
- This staining method is useful for detecting macrophages, including fetal types.
Conclusions:
- Periodic acid methenamine silver staining is a valuable tool for identifying macrophages.
- Fetal macrophages contain significant amounts of carbohydrates within their vacuoles.
- The functional role of fetal macrophages warrants re-evaluation based on their carbohydrate content.
