Immune cell alterations in a pristane‐induced lupus model in C57BL/6J mice

Abstract Background Systemic lupus erythematosus (SLE) is an autoimmune disease characterized by immune‐mediated inflammation affecting multiple organs and systems. The aim of this study was to establish and validate a pristane‐induced SLE model in C57BL/6J mice and analyze immune cell alterations. Methods Six‐week‐old female C57BL/6J mice were randomly assigned to two groups ( n = 6 per group). The pristane group received a single 0.5 mL intraperitoneal injection of pristane, whereas the control group received a single intraperitoneal injection of 0.5 mL saline. Urine samples were collected before injection and at 2, 4, and 6 months after injection to monitor urinary protein levels. Six months postinjection, the mice were euthanized, and serum, kidney, and spleen tissues were collected. Serum antinuclear antibody (ANA), double‐stranded DNA(dsDNA), and inflammatory cytokine levels (interleukin [IL]‐1β, IL‐6, tumor necrosis factor‐α) were quantified by enzyme‐linked immunosorbent assay. Histological alterations in kidney tissues were assessed using hematoxylin and eosin, periodic acid‐Schiff, Masson, and silver staining, in addition to direct immunofluorescence for immunoglobulin G and complement component 3. Flow cytometry was used to assess immune cell alterations in the spleen. Results Following the intraperitoneal injection of pristane, the mice exhibited a gradual increase in spleen size, body weight, and urinary protein levels. Serum levels of ANA, dsDNA, and inflammatory cytokines were elevated to varying degrees ( p < 0.05). Histological analysis of the kidney sections revealed characteristic nephritic alterations, including glomerular swelling and lymphocyte infiltration. In the spleen, T cell numbers decreased, whereas the proportion of myeloid cells significantly increased, particularly monocytes, neutrophils, and macrophages ( p < 0.05). Conclusion Pristane successfully induced a SLE model in C57BL/6J mice, characterized by nephritic injury and significant alterations in immune cell populations.