Housekeeping gene stability in pristane-induced arthritis and antigen-induced pulmonary inflammation of rats

Aim of this study is to explore the expression stability of 12 commonly used housekeeping genes in inflammation condition. Two rat models, pristane-induced arthritis (PIA) and antigen-induced pulmonary inflammation (AIPI) were established and reverse transcription-PCR was performed from rat spleens and inguinal lymph nodes. The reference gene expression fluctuated in the immune-associated tissues and 18S rRNA expression from the various inflammatory conditions was the most stably in all examined gene expression. Besides, peptidylprolyl isomerase A and beta-glucuronidase in PIA spleens, beta-actin and GAPDH in PIA inguinal lymph nodes, and peptidylprolyl isomerase A and beta-actin in AIPI spleens, expressed more stably than others. These results were further confirmed by expression study of TNF-alpha in PIA rat inguinal lymph nodes. We suggest that the stable gene mentioned above or geometric mean of three best references in each experimental condition should be used as the reference and the variable ones should be avoided in similar study designs.