Modulation of ß-adrenergic receptor in rat lung after gamma irradiation.

OBJECTIVES: To study the effect of γ irradiation on ß-adrenergic receptors of the lung. MATERIALS AND METHODS: Healthy Sprague-Dawley rats were used as an animal model. Cell membrane proteins of lung tissue were harvested after the whole lung received 20 Gy of 60Co γ irradiation. 125I-labeled iodopindolol (125I-IPIN) was used as a ligand of ß-adrenergic receptors. The numbers of the ß-adrenergic receptors were determined by radioligand-receptor binding assay (RBA). Data were compared with irreversible blockage using antagonist bromoacetylalprenololmenthan (BAAM). RESULTS: The post-radiation RBA assay showed that the number of ß-adrenergic receptors in lung tissue decreased at a steady rate. It decreased to 48% of the normal level at the 15th day after irradiation. At 40 days after radiation the level of ß-adrenergic receptors started to increase at a steady rate and reached to the normal level around 70 days after radiation. There were significant differences in receptor synthesis, degradation and regeneration rates between irradiation group and BAMM group. CONCLUSIONS: The whole lung irradiation could severely affect the levels of ß-adrenergic receptors. The potential clinical implications of radiation-induced changes of ß-adrenergic receptors warrant further investigation.

In vivo mouse

The aim of this in vivo study was to evaluate the feasibility of ^{99m}Tc-labeled cartilage link protein (CLP) probe for the single-photon emission computed tomography (SPECT) of lung cancer. Xenograft mouse model were established from a luciferase expressing cell line derived from a human lung cancer. Bioluminescence imaging (BLI) was carried out prior to ^{99m}Tc-CLP and ^{99m}Tc-methoxyisobutyl isonitrile (MIBI) SPECT scans. The image quality of ^{99m}Tc-CLP scan was validated with BLI and compared with well established ^{99m}Tc-MIBI scan. Results of multimodal imaging analyses suggested that ^{99m}Tc-CLP was a sensitive and reliable SPECT agent for lung cancer imaging.

[Feasibility of cartilage link protein of hyaluronic acid for defining radiotherapeutic target volume in a mouse model of lung tumor].

OBJECTIVE: To investigate the feasibility of using cartilage link protein of hyaluronic acid (HA-CLP) for defining the tumor boundary in a mouse model of lung carcinoma. METHODS: Lung carcinoma was induced in KM mice by chemical carcinogenesis. HA-CLP separated from bovine cartilage and purified by affinity chromatography was labeled with (125)I for autoradiography. Immunohistochemical analysis and Western blotting were used to examine the efficiency of HA-CLP in defining the boundaries of the lung tumors. RESULTS: With autoradiography, the clearest image of lung cancer was obtained at 2 h. With immunohistochemical method, the tumor boundary was the most clearly displayed at 2 h when the strongest signals of HA-CLP was detected; Western blotting also showed the clearest bands of HA-CLP at 2 h. CONCLUSION: HA-CLP has the immunogenicity of HABP, and can efficiently indicate lung tumor boundary in autoradiography and immunohistochemistry.