Effect of toxoplasmic infection on the biodistribution of a brain radiopharmaceutical

Abstract

Purpose: This study evaluated if Toxoplasma gondii infection and the drug-associated infection modifies the brain radiopharmaceutical Ethylene Cystine Diethylester Dihydrochloride (^99mTc-ECD) biodistribution in mice.

Materials and methods: A total of 18 mice were divided into 3 groups. Control group (C) received distilled water and ^99mTc-ECD; Infected group (I) received T. gondii strain and ^99mTc-ECD; Infected and Treated group (IT), in addition to infection, received association of Pyrimethamine and Sulfadiazine and ^99mTc-ECD. The T. gondii strain used in this study was TgCkRrRN3. Forty minutes after administration of the ^99mTc-ECD, all animals were euthanized, and blood and brain samples were isolated. The counting of the radioactivity percentage per gram of tissue (%ATI/g) was calculated, and statistical analysis was performed by t-test, with a level of significance of p < .05.

Results: There was a significant increase in %ATI/g between groups C and I on brain (0.35 ± 0.02 and 0.45 ± 0.04; p = .041) and on blood (0.80 ± 0.09 and 1.14 ± 0.31; p = .049). A significant decrease in %ATI/g occurred between groups C and IT on blood (0.80 ± 0.09 and 0.54 ± 0.08; p = .001) and on brain (0.35 ± 0.02 and 0.22 ± 0.04; p = .049).

Conclusions: Combined therapy of anti-Toxoplasma drugs in infected mice reduced the uptake of ^99mTc-ECD, probably due to its binding to plasma proteins.

Keywords:

• Toxoplasma gondii
• parasitic infection
• sulfadiazine
• pyrimethamine
• radiopharmaceuticals

Acknowledgments

The authors thank the Norteriograndense League against Cancer, Natal/RN, Brazil, for donating radiopharmaceuticals and to the Center of Experimental Surgery of the Center of Health Sciences (UFRN), for counting of the radioactivity in an automatic gamma counter. Our thanks also go to the anonymous referee for many invaluable corrections and suggestions.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Notes on contributors

João Cláudio da Costa Urbano

João Cláudio da Costa Urbano, is Graduate Student, School of Medicine (UFRN), Natal, Brazil.

Ranny Beatriz de Carvalho Holanda Leite

Ranny Beatriz de Carvalho Holanda Leite, is Graduate Student, School of Medicine (UFRN), Natal, Brazil.

Renan Leopoldo Pereira Castro

Renan Leopoldo Pereira Castro, is Graduate Student, School of Medicine (UFRN), Natal, Brazil.

Clarice Maux Vianna da Silva

Clarice Maux Vianna da Silva, is Graduate Student, School of Medicine (UFRN), Natal, Brazil.

Joelma Maria de Araújo Andrade

Joelma Maria de Araújo Andrade, is Master Student of LABMAT/UFRN.

Cláudio Bruno Silva de Oliveira

Cláudio Bruno Silva de Oliveira is PhD in Preclinical and clinical trials at LABMAT/UFRN and Professor at UNINASSAU College.

Vanessa Santos de Arruda Barbosa

Vanessa Santos de Arruda Barbosa is an Associate Professor of the Center for Education and Health/UFCG, Campina Grande, Brazil, contributed to the statistical analyzes of the results and to the final version of the manuscript.

Valter Ferreira de Andrade-Neto

Valter Ferreira de Andrade-Neto is Professor at UFRN and Head of LABMAT, conducted the research using Toxoplasma gondii-murine model and contributed to the final version of the manuscript.

Cecília Maria de Carvalho Xavier Holanda

Cecília Maria de Carvalho Xavier Holanda is an Associate Professor at UFRN, Head of Laboratory of Experimental Bioavailability and Antiparasitic Tests-LEABE, conducted all the experiments of research, supervising the medical students, and wrote the manuscript, including its final version.