OSHODIN PEACE OSARIEMEN

With a heart full of gratitude, I first give all glory and thanks to GOD ALMIGHTY for His unfailing love, guidance, and provision, which has carried me through every stage of this project. I am deeply grateful to my supervisor, DR. AUSTIN IROGHAMA ARHOMAREN, whose patience, guidance, and encouragement were instrumental to the success of this work. My heartfelt appreciation also goes to my Head of Department, DR. (MRS.) ZAINAB OMORUYI, for her motherly leadership and constant encouragement. I remain thankful to all my lecturers PROF. OSIME, DR. MRS. OBAZELU, DR. MRS. OTIKOR, MR.UZAMERE, DR. OSAKWE, DR. ERHABOR, and DR. MRS. OTUTU and others for their dedication, teachings, and the wealth of knowledge they have imparted in me. To my beloved parents, MR. AND MRS. FRIDAY OSHODIN, I owe special thanks for their sacrifices, prayers, and unwavering support. I am equally grateful to my siblings JOY, RUTH, EFOSA, BLESSING, AIMUA , for their love, encouragement, and constant belief in me. I also appreciate the prayers, fellowship, and spiritual covering of my place of worship, CHRIST IMPACT ASSEMBLY, which has been a pillar of strength to me all through my journey so far. Finally, my warmest appreciation goes to my dear friends DIVINE, ABEL, FAVOUR, ELIZABETH, JESSICA and my senior colleague, MICHEAL, for their encouragement, support, and friendship all through this journey.

Ionizing radiation from diagnostic imaging procedures has raised concerns regarding its potential biological effects, even at low doses. This study investigated the impact of diagnostic radiation exposure on mRNA expression of p53 and DIAP1 in Drosophila melanogaster. Healthy laboratory-reared flies (Harwich strain) were divided into five groups (n=100 per group): a control group (Group A), two X-ray–exposed groups (Group B, 0.1 Gy daily for 7 days; Group C, 0.1 Gy daily for 14 days), and two CT-exposed groups (Group D, 0.1 Gy daily for 7 days; Group E, 0.1 Gy daily for 14 days). Radiation exposure was performed under standardized laboratory conditions at the Biomedical Toxicology Chemicals Safety (BIOTOXCS) Research Laboratory, University of Benin. After exposure, flies were preserved in Trizol reagent for RNA extraction, followed by cDNA synthesis and semi-quantitative PCR analysis. Results showed a significant upregulation of p53 and DIAP1 mRNA expression in radiation-exposed groups compared to the control (p<0.05). Expression levels were dose- and duration-dependent, with Groups C and E (14-day exposures) exhibiting the highest increases. Gel electrophoresis and bar chart analyses further confirmed these findings, demonstrating progressive changes consistent with prolonged radiation stress. These results indicate that even low-dose diagnostic radiation can induce molecular alterations in stress- and apoptosis-related genes in Drosophila melanogaster. The study underscores the utility of Drosophila as a model organism for assessing radiation-induced genetic responses and highlights the need for further research into the implications of cumulative diagnostic radiation exposure.