LAUSR

Abstract The current study aimed to characterize different stages of rodlet cells using light microscopy, immunohistochemistry, and transmission electron microscopy. Granular rodlet cells have a distinct granular cytoplasm. Transitional rodlet cells had distinct capsules, and immature granules. Mature rodlet cells were pear-shaped and had elongated granules. Ruptured rodlet cells had a granular cytoplasm. The affinity of rodlet cells for different histochemical techniques was detected. Immunohistochemical analysis of rodlet cells for stem cell markers such as CD117, CD34, proliferation marker, proliferating cell nuclear antigen (PCNA), endopeptidase activity; matrix metalloproteinase-9 (MPP-9) and the angiogenic factor; vascular endothelial growth factor (VEGF) was investigated. All stages of rodlet cells were expressed CD117. However, the ruptured stage was CD117-negative. The granular, transitional, and mature stages had strong CD34 immunoaffinity, while the ruptured rodlet cells were CD34-negative. The most potent immunoreactivity for PCNA was the granular rodlet cells. The transitional cells exhibited less immunoreactivity, while mature rodlet cells had no immunoaffinity for PCNA. All stages of rodlet cells had high enzyme activity as indicated by Acridine orange and exhibited strong MPP-9 immunoaffinity. VEGF is mostly expressed by granular, transitional, and mature rodlet cells. In conclusion, rodlet cells relatively had stemness properties, endopeptidase activity, express a proliferation marker, and angiogenic factors. We suggest a potential role of rodlet cells in immune defense.