The effect of traditional risk factors for stone disease on calcium oxalate crystal adherence in the rat bladder

Crystal growth, a research-driven laboratory course

The research-driven laboratory experiment described herein has at its core the individual development of students, combining core subject matter with the opportunity to explore, in a research environment, areas outside of traditional curricula; however, it maintains the pedagogical training for an undergraduate major degree in chemistry and sciences in general. The laboratory can feasibly be implemented in high schools to expose students to an engaging and intellectually fulfilling aspect of chemistry early in their career. This seven-week project is based on the growth and study of crystals and encourages students, from the outset, to conceive, propose, design, plan and carry out their own research on chemicals and conditions of their own choosing. The wide array of laboratory equipment, analytical instrumentation and techniques that the students are potentially exposed to, from micropipettes and optical microscopes to scanning electron microscopy and powder X-ray diffraction, puts these projects on a par with senior capstone research projects. The feedback from the students for the seven years this project has been in operation is almost unanimous in enthusiasm and praise.

High Concentration of Calcium Stimulates Calcium Oxalate Crystal Attachment to Rat Tubular Epithelial NRK Cells Through Osteopontin

OBJECTIVE

To address whether hypercalciuria can stimulate calcium oxalate (CaOx) crystal deposition in kidney through osteopontin (OPN).

MATERIALS AND METHODS

Rat tubular epithelial NRK cells were exposed to calcium. The cell viability, the cellular malondialdehyde content as a marker of reactive oxygen species (ROS), and the release of lactate dehydrogenase as markers of injury were detected. The production and gene expression of OPN were also examined. CaOx crystal attachment to cells was accomplished by measuring the calcium concentration of the cell lysates with atomic absorption analysis.

RESULTS

Exposure to calcium produced signs of cell injury and ROS-induced lipid peroxidation. The messenger ribonucleic acid expression and production of OPN increased significantly. OPN knockdown can significantly decrease the amount of CaOx crystal attachment to NRK cells.

CONCLUSION

In response to exposure to high concentration of calcium, renal tubular epithelial NRK cells increase the production of OPN, which may have a promoting role in CaOx crystal adhesion to NRK cells by calcium stimulation.