engleski

Bone phenotype of IL-7 transgenic mice

To investigate the bone phenotype of IL-7 transgenic mice. IL-7 is one of the major cytokines active in early mouse B lymphopoiesis. Overexpression of IL-7 changes B cell development causing lymphadenopathy, characterized by the accumulation of CD45R (B220) positive cells, which retain the potential for differentiating into diverse hematopoietic lineages, including osteoclasts. Tibiae from 6 or 12 month-old mice were processed for histology, serial sections were stained with Goldner's trichrome stain and the percentage of trabecular bone was measured using Osteomeasure software. Osteoclasts were identified by tartrate-resistant acid phosphatase (TRAP) staining and counted on serial sections. Bone marrow cells were cultured with recombinant murine receptor activator of NF-κ B ligand (RANKL 20μ g/ml) and recombinant murine macrophage colony stimulating factor (M-CSF 20μ g/ml) to stimulate osteoclast-like cell (OCL) formation. After 6 days of culture, TRAP positive cells with three or more nuclei per cell were counted per well. Single cell suspensions were prepared from bone marrow and peripheral blood. Different cell populations were identified using fluorescent labeling, followed by flow-cytometric analysis. Staining for flow-cytometry was performed using following antibodies: anti CD45R and CD19 (B-cell development markers), CD11b (monocyte-macrophage population marker), and CD3 (T-cell surface marker). The percentage of trabecular bone was decreased in IL-7 transgenic mice compared with wild type mice, more noticeable in older mice. IL-7 transgenics had more TRAP positive osteoclasts on both bone surfaces and in bone marrow cell cultures. The proportion of CD45R positive cells was increased three or four fold in bone marrow of IL-7 transgenic mice, but there was no significant difference in the proportion of this cell population or in CD45R/CD11b positive cells population in the peripheral blood. Our results suggest a specific bone phenotype in IL-7 transgenic mice, characterized by a decrease in the trabecular bone volume, which is the result of an increased osteoclast number and consequently increased bone resorption. Further investigation is needed to explore the osteoclast functionality and to identifiy the possible role of the CD45R positive population as osteoclasts precursors.

Bone Phenotype; IL-7; Transgenic mice

Rad je kao poster prezentiran i na skupu Annual Meeting of Croatian Immunological Society, održanom od 29.09.-02.10.2005.g., Dugi otok, Hrvatska ; objavljen u Knjizi sažetaka sa skupa ; Rijeka : Medicinski fakultet, 2005. ; str. 31-31.