Different patterns of interleukin-1α and interleukin-1β expression in organs of normal young and old mice

The different physiological roles of interleukin-1α (IL-1α) and interleukin-1β (IL-1β) are not well understood, especially when considering the apparent overlap and redundancy of the two IL-1 molecules. Characterization of IL-1α and IL-1β expression was performed in this study in organs from young and old mice, using immunohistochemistry and ELISA (enzyme-linked immunosorbent assay). The results indicate that organ IL-1α and IL-1β display different patterns of expression: IL-1α is manifested more prominently in lymphoreticular organs (lungs, small intestine, spleen, liver), while IL-1β is more evident in highly specialized and more vulnerable organs, which do not play a leading role in defense against infections and intoxication (heart, brain, skeletal muscle, kidney). This differential expression is more accentuated in old mice, possibly pointing to the special relevance of these cytokines to organ homeostasis in old age. These findings may shed new light on the physiological functions of IL-1α and IL-1β, and may also lead to the development of improved therapeutic approaches, based on the specific manipulation of these cytokines.