There is a rapid onset of organizing alveolitis/fibrosis at 120-140 d after whole lung irradiation of C57BL/6J mice. To test the hypothesis that circulating cells of bone marrow origin contribute to irradiation fibrosis, irradiated chimeric green fluorescent protein (GFP)+ C57BL/6J mice were followed for GFP+ cells in areas of lung fibrosis. In a second experimental model, C57BL/6J female mice received 20 Gy total lung irradiation, and after 60 or 80 d were intravenously injected with cells from a clonal GFP+ male bone marrow stromal cell line or male GFP+ whole bone marrow, respectively. The mice were then followed for the development of pulmonary fibrosis, and the contribution of Y-probe-positive, GFP+ cells to fibrotic areas was quantitated. Bromodeoxyuridine labeling of developing fibrotic areas showed that the cell division occurred predominantly in GFP+, Y-probe-positive, and vimentin-positive cells. Immunohistochemistry demonstrated that these cells were macrophages and fibroblasts, not endothelial cells. Mice that received manganese superoxide dismutase-plasmid/liposome intratracheal injection 24 h before total lung irradiation demonstrated a decrease in GFP+ fibroblastic cells in the lung. Thus, pulmonary irradiation fibrosis contains proliferating cells of bone marrow origin, and gene therapy prevention of this condition acts in part by decreasing the migration and proliferation of marrow origin cells.

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The growth of mesoporous quasi‐single‐crystalline Co3O4 nanobelts by topotactic chemical transformation from α‐Co(OH)2 nanobelts is realized. During the topotactic transformation process, the primary α‐Co(OH)2 nanobelt frameworks can be preserved. The phases, crystal structures, morphologies, and growth behavior of both the precursory and resultant products are characterized by powder X‐ray diffraction (XRD), electron microscopy—scanning electron (SEM) and transmission electron (TEM) microscopy, and selected area electron diffraction (SAED). Detailed investigation of the formation mechanism of the porous Co3O4 nanobelts indicates topotactic nucleation and oriented growth of textured spinel Co3O4 nanowalls (nanoparticles) inside the nanobelts. Co3O4 nanocrystals prefer [0001] epitaxial growth direction of hexagonal α‐Co(OH)2 nanobelts due to the structural matching of [0001] α‐Co(OH)2//[111] Co3O4. The surface‐areas and pore sizes of the spinel Co3O4 products can be tuned through heat treatment of α‐Co(OH)2 precursors at different temperatures. The galvanostatic cycling measurement of the Co3O4 products indicates that their charge–discharge performance can be optimized. In the voltage range of 0.0–3.0 V versus Li+/Li at 40 mA g−1, reversible capacities of a sample consisting of mesoporous quasi‐single‐crystalline Co3O4 nanobelts can reach up to 1400 mA h g−1, much larger than the theoretical capacity of bulk Co3O4 (892 mA h g−1).

Pulmonary toxicity is a major complication of total body irradiation used in preparation of patients for bone marrow transplantation. The mechanism of the late pulmonary damage manifested by fibrosis is unknown. In C57BL/6NHsd mice, manganese superoxide dismutase-plasmid/liposome (MnSOD-PL) intratracheal injection 24 hours prior to 20 Gy single-fraction irradiation to both lungs significantly reduced late irradiation damage. Single intratracheal injections of MnSOD-PL, at concentrations as low as 250 microg of plasmid DNA, in a constant volume of 78 microL of liposomes, reduced late damage. To determine whether a slowly proliferating population of cells in the lung was responsible for initiation of fibrosis and was altered by MnSOD-PL therapy, 20 Gy total lung-irradiated mice were examined at serial time points for bromodeoxyuridine (BrdU) uptake in sites of cell division. There was low-level, but nonsignificant, increased cell proliferation detected at 80 days, with a significant increase at 100 days, 120 days, and at the time of death. Immunohistochemical assay for up-regulation of adhesion molecules associated with recruitment, transendothelial migration, and proliferation of bronchoalveolar macrophages revealed significant up-regulation of vascular cell adhesion molecule-1 (VCAM-1) and intracellular adhesion molecule-1 (ICAM-1) at 100 days with further increases up to the time of death. Increases were first detected in endothelin-positive endothelial cells. MnSOD-PL administration prior to irradiation decreased both BrdU incorporation and delayed expression of VCAM-1 and ICAM-1. The data indicate that the appearance of late irradiation-induced pulmonary fibrosis is associated with the up-regulation of adhesion molecules and suggest that potential targets for intervention may focus on the pulmonary vascular endothelium.

Oral cavity mucositis is a major toxicity of radiation therapy for head and neck cancer. In the present mouse model studies, we evaluated intraoral administration of SOD2-PL complexes 24 h before single-fraction 30-Gy irradiation for the prevention of oral cavity mucositis. Expression of the human SOD2 transgene in the oral cavity of C3H/HeNsd mice was demonstrated by nested reverse transcriptase polymerase chain reaction (RT-PCR). Mice treated intraorally with bacterial beta-galactosidase gene-plasmid/liposome (LacZ-PL) or hemagglutinin (HA)-manganese superoxide dismutase-plasmid/liposome (HA-SOD2-PL) demonstrated LacZ or HA-SOD2 expression, respectively, 24 h after injection. In a second strain of mouse, SOD2-PL-treated female athymic nude mice demonstrated significantly decreased ulceration at day 5 after 30 Gy, compared to LacZ-PL-injected, irradiated mice or irradiated controls. No further reduction in radiation-induced ulceration was detected in mice treated with both SOD2-PL and 10 mg/kg of amifostine (WR-2721) 30 min before 30 Gy compared to SOD2-PL alone. No significant protection of orthotopically transplanted murine squamous cell carcinoma (SCC-VII) tumors was detected in mice that received SOD2-PL treatment before 18 Gy. Thus overexpression of human SOD2 in the oral cavity mucosa can prevent radiation-induced mucositis with no detectable compromise in the therapeutic response of orthotopically transplanted tumors.

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