Preparation of 99mTc-Carnosine and 99mTcO-(V)-DMSA Complexes, Biological Distribution, and Estimation of Their Gene Anti- Polymorphisms Induced by -Irradiation

摘要

Background: Two chelating agents (Carnosine and DMSA) were used to study their labeling conditions with technetium-99m followed by biological distribution investigation. Molecular studies were done via PCR/RFLP analysis of angiotensin II subtype II receptor gene for monitoring their antioxidant activity through free iron chelation leading to inhibition of Fenton reaction. Material and methods : Carnosine was labeled by mixing 4 mg with 30 mg glucose and 25 g SnCl2.2H2O, followed by pertechnetate and stand at room temperature for 60 minutes. Minor modification was done to prepare 99mTc(V)-DMSA tracer in one step, by adding pertechnetate solution to the lyophilized kit contains 1mg DMSA, 0.1 mg SnCl2.2H2O, and 30 mg glucose at pH 9. The biodistribution of the two tracers in normal and tumor-induced mice. The molecular investigation of the anti-oxidant activity of both carnosine and DMSA in 6 Gy - irradiated rats using the anti-inflammatory angiotensin II subtype II receptor gene (AT2RG) as indicator. Results: Carnosine and DMSA were labeled with Technetium-99m yielding 85% and 97%, respectively the ability of both tracers to localize in tumor sites but the priority to the 99mTc (V)-DMSA. Molecular studies showed strong antioxidant activity of carnosine but not enough to block radiation induced oxidative stress and Moderate antioxidant activity of DMSA was achieved by chelating free iron and iron released through oxidative stress. Maximum protection was achieved through the dual action of both DMSA and carnosine. Conclusion: moderate and high labeling yield were achieved for both 99mTc(V)DMSA and 99mTc-canosine respectively with higher selectivity of the former to tumor sites and maximum protection were achieved by the dual action of both chelating agents