Ethylene glycol induces calcium oxalate crystal deposition in Malpighian tubules: a Drosophila model for nephrolithiasis/urolithiasis

Abstract

Several animal species are used to study calcium oxalate urolithiasis; however, an ideal model has yet to be identified. We used Drosophila as a model organism and fed the flies lithogenic agents such as ethylene glycol, hydroxyl-L-proline, and sodium oxalate. At different times, the Malpighian tubules, the kidney equivalent of insects, were dissected and a polarized light microscope used to highlight the birefringent crystals. Scanning electron microscopy and energy-dispersive X-ray spectroscopy confirmed that the crystal composition was predominately calcium oxalate. Furthermore, administration of potassium citrate successfully reduced the quantity of and modulated the integrity of the ethylene glycol-induced crystals. Thus, the Drosophila model of bio-mineralization produces crystals in the urinary system through many lithogenic agents, permits observation of crystal formation, and is amenable to genetic manipulation. This model may mimic the etiology and clinical manifestations of calcium oxalate stone formation and aid in identification of the genetic basis of this disease.

Antioxidative mechanism involved in the preventive efficacy ofBergenia ciliatarhizomes against experimental nephrolithiasis in rats

“…However, it has been proven that oral intake of EG in rats caused significant hyperoxaluria with CaC 2 O 4 crystalluria rather than the formation of papillary plaques or stones (Chen et al, 2011). As traditional medicines are usually taken by the oral route, the same route of administration was followed in our study for the evaluation of preventive effect of the B. ciliata rhizomes against EG induced nephrolithiasis in rats.…”

Proteomic changes in response to crystal formation inDrosophilaMalpighian tubules

“…More studies will be desirable to elucidate the biological process of how these differentially abundant proteins function as a whole in the process of CaOx crystal formation. Though previous researchers 4,10 have shown the crystals inside the Malpighian tubules to be CaOx, there was the possibility given that the relative elemental composition was altered during prolonged feeding. One of the other limitation of the current study is the lack of functional validation of the candidate proteins.…”

“…The crystal composition has been shown to be predominantly CaOx monohydrate or CaOx dihydrate by energy-disperse X-ray spectroscopy and scanning electron microscopy in previous studies. 4,10 Qualitative analysis of detected proteins in 3 biological replicates in Mascot analysis Initially, the MASCOT (v2.5.1, Matrix Science) search engine was used to interrogate the Malpighian tubule proteome in order to generate a comprehensive list of all detected proteins in 3 experimental conditions. Only proteins common in the 3 biological replicates were further analyzed in sub-categories.…”

“…[5][6][7][8] Drosophila has also been reported to reliably develop calcium oxalate (CaOx) crystals with dietary supplements of stone-forming agents. 4 The simplicity and transparent nature of Malpighian tubules allows for direct observation and quantification of crystals, which is not possible in other animal models.…”

“…4 The advantages of Drosophila over other animal models include similar anatomical structure and philological function of Malpighian tubule to human renal tubules, brief life cycle and the ease and low cost of rearing. [5][6][7][8] Drosophila has also been reported to reliably develop calcium oxalate (CaOx) crystals with dietary supplements of stone-forming agents.…”