Combined injection of pristane and Bacillus Calmette-Guerin Vaccine successfully establishes a lupus model with atherosclerosis

Cardiovascular disease (CVD) induced by atherosclerosis (AS) is the main fatal complication of systemic lupus erythematosus (SLE). Establishing an appropriate animal model of SLE with AS is of great value for investigating the pathogenesis and therapeutic targets of SLE-CVD. In the present work, pristane was injected intraperitoneally into C57BL/6J mice to establish the SLE model and Bacillus Calmette-Guerin Vaccine (BCG) was injected intradermally one month later to enhance immunity and induce AS. Both pristane or pristane and BCG treated C57BL/6J mice exhibit a classical lupus-like phenotype which manifested as proteinuria and high levels of serum anti-ANA and anti-dsDNA autoantibodies, in conjunction with pathological changes in spleen and kidney, complement C3 deposition in the kidney, overactivation of T and B cells, a decreased proportion of splenic CD19⁺ B cells, and an increased frequency of CD19⁻CD138⁺ plasma cells, CD19⁺CD27⁺ memory B cells, CD3⁺CD4⁺ helper T (Th) cells, and CD3⁺CD4⁺CXCR5⁺PD-1⁺ T follicular helper cells. The combined pristane and BCG challenge aggravated AS in SLE mice, which had an enlarged thymus gland, an increased T cell proliferative vitality, an expanded Th cell pool, severe perivascular lymphocytes, and CD68⁺ macrophage infiltration, in addition to an intimal lipid deposition, and further elevation of Toll-like receptor 2 (TLR2), TLR4, and the transcription factor nuclear factor-κB (NF-κB) expression in kidney tissue and blood vessels when comparing with pristane or BCG injection alone. Pristane combined BCG challenge is able to establish a validated SLE-AS mouse model in C57BL/6J mice.