Abstract

AFFONSO JUNIOR, Renato José et al. In vivo evaluation of expression of TGFb1 in the irradiated heart. Radiol Bras [online]. 2004, vol.37, n.2, pp.107-113. ISSN 1678-7099.  https://doi.org/10.1590/S0100-39842004000200008.

OBJECTIVE: To assess the latent and active TGFb1 localization in the heart, to evaluate whether or not radiation induces latent TGFb1 activation, and to study the distribution of collagen fibers in the irradiated heart. MATERIALS AND METHODS: Thirty-two C57BL mice were randomly assigned in two groups: GI (non irradiated animals) and GII (irradiated animals). The mice from GII received a single whole-body radiation dose of 7Gy, using a ⁶⁰Co source at a dose rate of 0.97 Gy/min. The animals were sacrificed by cervical dislocation at 1, 14, 30 and 90 days after irradiation. RESULTS: The irradiated hearts showed: 1) nuclear changes and muscle cells with decreased striations; 2) significant increase in the collagen deposition 90 days after irradiation; 3) latent TGFb1 activation in the cardiomyocytes and connective tissue cells after irradiation. CONCLUSION: Our results show the importance of TGFb1 protein in the process of radiation-induced heart fibrosis and suggest that cardiomyocytes and connective cells may play a role in this mechanism acting as cellular sources of active TGFb1.

Keywords : Ionizing radiation; Heart fibrosis; Transforming growth factor b (TGFb).

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