An X-ray micro-computer tomography study of the Malpighian tubules of the Blue Bottle Blow Fly (Calliphora vomitoria) Diptera: Calliphoridae.

Malpighian tubules are the insect equivalent of mammalian kidneys and normally drain into the gut at the junction between the mid and hind gut. The Malpighian tubules of the fruit fly Drosophila melanogaster are increasingly being used as a model for studying human renal tract development, histology, nephrolithiasis and urolithiasis. In the present study we report when using X-ray micro-computer tomography techniques, the larval, intrapuparial and adult stages of the larger Calliphora vomitoria can contain large amounts of calcium-rich concretions which are tightly packed in the lumen of both anterior Malpighian tubules. We show that it is feasible to utilise these calcium-rich concretions as a form of marking agent to delineate the various developmental stages of the Malpighian tubules including the crucial phase when the Malpighian tubules reconnect with the hind gut. In the majority of cases during the intrapuparial period the ureters of the Malpighian tubules did not start to re-canalise and thus reconnect with the developing hind gut until the 7th day of the 10-11 day. Just prior to ecdysis, virtually all the radio-opaque concretions in the Malpighian tubules had emptied into the hind gut and had then been completely excreted by the time the imago emerged from its puparium. In contrast, we show that in flies developing from larvae previously stained by ingesting Rhodamine B, a known substrate for both the Multi Xenobiotic Resistance and Multi Drug Resistant membrane transport systems, the efficiency with which these calcium-rich concretions are excreted by the imago as it emerges from its intrapuparial period can be significantly impaired. Therefore, it might be useful to include C. vomitoria as a model when studying renal tract development and urolithiasis using X-ray micro-computer tomography.

Toward a new insight of calcium oxalate stones in Drosophila by micro-computerized tomography.

We previously developed an animal model of calcium oxalate (CaOx) deposition on the Malphigian tubules of Drosophila melanogaster as a model of urolithiasis. Here, we introduce a new tool for the study of anatomical structure for Drosophila. As a consequence of technical development, the invention of micro-computerized tomography (CT) has been introduced to the small animal, such as rat and mice. We used Drosophila as a model organism and fed the flies 0.5% lithogenic agent ethylene glycol for 3 weeks. Samples were simply prepared for further scanned by micro-CT to scan samples at 800 nm resolution. CT scanning was performed at 40 kVp of voltage, 250 µA of current, and 1750 ms of exposure time and without filter. Reconstruction of sections was carried out with the GPU-based scanner software. Specific region of interests was further analyzed by DataViewer software. Area with high radiologic density level was defined as CaOx deposition for further 3D analysis. Image of whole lithogenic Drosophila was compared with control. High radiologic density level was detected in the region of Malphigian tubules which can be identified as CaOx stones. There was no stone image in the control group. The image was the same as human non-contrast CT for the diagnosis of stone disease. Micro-CT clearly demonstrated the calcium oxalate calcifications in the Malphigian tubules of fruit fly. The image system provides that a new vision on study animal will facilitate further study of stone disease. With the development of new technology on micro-CT, more delicate and advanced image will be presented in the future.