Bone marrow-derived cells contribute to regeneration of injured prostate epithelium and stroma.

BACKGROUND

Recent studies have reported that bone marrow-derived cells (BMDCs), which are recruited to sites of tissue injury and inflammation, can differentiate into epithelial cells, such as liver, lung, gastrointestinal tract, and skin cells. We investigated the role of BMDCs in contributing to regeneration of injured prostate epithelium.

METHODS

Using chimera rats that received allogenic bone marrow grafts from green fluorescent protein (GFP) transgenic rats after lethal whole-body irradiation, we investigated the existence of epithelial marker-positive BMDCs in injured prostate tissue caused by transurethral injection of lipopolysaccharide.

RESULTS

Prostate tissues were harvested 2 weeks after transurethral lipopolysaccharide injection. Immunofluorescence staining showed that some cells in the stroma co-expressed GFP and pan-cytokeratin, which suggested the existence of epithelial marker-positive BMDCs. To confirm the existence of such cells, we collected bone marrow-derived non-hematopoietic cells (GFP+/CD45- cells) from the prostate by fluorescence-activated cell sorter analysis and analyzed the characteristics of the GFP+/CD45- cells. The number of cells in this population significantly increased from 0.042% to 0.492% compared with normal prostate tissue. We found by immunofluorescent analysis and RT-PCR that GFP+/CD45- cells expressed cytokeratin, which suggested that these cells have some features of epithelial cells. In the prostate obtained from the chimera rats 34 weeks after lipopolysaccharide injection, GFP- and cytokeratin-positive cells were observed in the prostate gland, which suggested that some of the cells in the prostate gland regenerated after prostate inflammation derived from bone marrow.

CONCLUSIONS

BMDCs might be able to differentiate into prostate epithelial cells after prostatic injury.