It shows that the number of apoptotic cells increase as the radiation dose is escalated from 0 to 8 Gy. Figure 5 TUNEL assay for S180 transplant sarcoma after irradiation. In pathological sections of

S180 sarcoma after irradiation (× 100), the black arrow indicates the TUNEL positive apoptotic cells. It shows that the number of apoptotic cells increases as radiation of 8 Gy is delivered comparing to that of the 0 Gy control. The degree of tracer uptake in tumor correlated well with the apoptotic rate evaluated by TUNEL assay. In EL4 lymphoma, the apoptotic rate significantly increased as the dose increased from 2 to 8 Gy (Table 2). In S180 sarcoma, the apoptotic rate measured by TUNEL assay was significantly higher in the 8 Gy group than that in 0 Gy group (Table 3). Similar to the biodistribution results, MNK inhibitor the corresponding apoptotic rate measured by TUNEL in the EL4 lymphoma was also significantly higher than that of the S180 sarcoma for both 0 Gy (P = 0.017) and 8 Gy (P < 0.001). The increment of apoptotic cells at 8 Gy relative to 0 Gy was less in find more S180 sarcoma than that in the EL4 lymphoma, which agrees well with the TAVS imaging results. As shown in Figure 6, when data from all tumor

samples were combined (EL4 and S180 tumors were not distinguished from each other), it could be observed that the number of apoptotic cells (abscissa) was linearly correlated with the percentage of99mTc-HYNIC- annexin V taken up by all tumors Buspirone HCl (ordinate), with a correlation coefficient (r) of 0.892 and a corresponding P value of < 0.001. These results

indicated that the degree of radiation induced apoptosis in tumor could be selleck chemicals llc represented by the99mTc-HYNIC- annexin V activity taken up in EL4 and S180 tumors. However, there are systematic deviations of points from the line, e.g., a sigmoid between 0.08 and 0.28 on the ordinate followed by a more gradual linear increase between 2.8 and 4. Figure 6 Correlation of TUNEL positive cells and 99m Tc-HYNIC-annexin V uptake in EL4 and S180 tumors. The plot shows the number of apoptotic cells (TUNEL positive) is linearly correlated with the uptake of the radio-labeled Annexin-V in the murine transplant tumors, showing that the Annexin-V imaging may illustrate different degrees of radiation induced apoptosis. Tumor regression after irradiation To evaluate the tumor response to radiation, the regression of EL4 lymphoma and S180 sarcoma in mice after single-dose irradiation with 8 Gy was observed (Figure 7). Without irradiation (0 Gy), the EL4 lymphoma grew with a daily increment of 0.1 cm in diameter and reached 5.1 cc (SD = 1.1) 13 days after tumor inoculation in mice. After a single 8 Gy irradiation, the EL4 lymphoma began to shrink on the second day and the tumor underwent significant necrosis on the 6th day after irradiation and disappeared completely on day 13.