Ultrastructural events in early calcium oxalate crystal formation in rats

A model system is described for the induction of renal calcium oxalate crystals with intraperitineal injections of sodium oxalate in rats. Early crystals are formed predominantly in cortical areas. Massive amounts of calcium are associated with this process, as demonstrated by potassium pyroantimonate staining. Actual crystal formation appears to be an involved process associated with calcium, oxalate, and cellular membranes. Although overt stone formation was not observed, we feel that the intimate involvement of membranes during crystal formation may be similar to that found in renal stones.