| Popis: |
The intraperitoneal administration of exogenous ATP prior to a lethal dose (7 Gy) of whole body neutron irradiation increased the radioresistance of BALB/c mice. This radiation used the beam from a neutron therapy facility produced by the reaction p(66 MeV)/Be. Survival of the mice, determined 7 days post-irradiation as the endpoint, was increased from 26% to 86% by the action of the exogenous ATP. Furthermore, the response of acid phosphatase activity as an indicator of the acute radiation effects showed a marked augmentation in both tissues studied, testes and small intestine. The activity of the enzyme after neutron irradiation with prior administration of ATP showed smaller increases when compared with the increases observed after neutron irradiation alone. This implies that exogenous ATP reduces the effect of the lytic enzyme and, hence, damage. Finally, changes were observed in the activity of acid phosphatase in the testes and intestine with different concentrations of exogenous ATP. In both tissues there was a monotonic decrease in the activity of the enzyme with increase of the concentration of exogenous ATP administrated before radiation. These results reflect the protective ability of exogenous ATP as an adaptive defence mechanism to reduce radiation damage in normal tissues after a lethal dose of neutron radiation. |
