A modified in vitro tool for isolation and characterization of rat quiescent islet stellate cells

Islet stellate cells (ISCs) play a critical role in islet fibrosis, contributing to the progression of pancreatic diseases. Previous studies have focused on fibrosis-associated activated ISCs obtained by standard islet explant techniques. However, in vitro models of quiescent ISCs (qISCs) are lacking. This study aims to develop a method to isolate qISCs and analyze their phenotype during activation.

Immunofluorescence staining was applied to localize ISCs in normal human, rat, and mouse islets. qISCs were isolated from rat islets using density gradient centrifugation (DGC) method. qRT-PCR, immunoblotting, proliferation, and migration assays were employed for their characterization.

Desmin-positive ISCs were detected in normal human, rat, and mouse islets. Freshly isolated qISCs, obtained by density gradient centrifugation, displayed a polygonal appearance with refringent cytoplasmic lipid droplets and expressed transcriptional markers indicating a low activation/quiescent state. With increasing culture time, the marker expression pattern changed, reflecting ISC activation. qISCs contained more lipid droplets and exhibited lower proliferation and migration abilities compared to spindle-shaped ISCs obtained by traditional explant techniques.

This study describes a new method for efficient isolation of qISCs from rat islets, representing a useful in vitro tool to study the biology of ISCs in more physiological conditions.