Effects of Freeze-Thawing, Storage Medium, and Incubation on the Streaming Potentials of Bone in Vitro

Abstract

Streaming potentials were determined as an index to electrokinetic change since they are more easily obtained than their electrokinetic inverse (electroosmosis). Results of earlier studies concerning electroosmosis of bone in vitro had suggested that storage of bone at -80 C and subsequent thawing changed the electrokinetic characteristics of bone. the present study determined the streaming potential of bone with 0.9% NaCl before and after storage of bone at -80 C for 1 week in 0.9% NaCl and found that freeze-thawing resulted in a significant reduction in streaming potential (P <0.001). When bones were stored in Waymouth's medium 752/1, pH 7.09 for 2 weeks, instead of in 0.9% NaCl, there was a significant increase in the streaming potential of bone (P <0.005). Bones incubated at 56°C for 45 minutes in 0.01 M HEPES, pH 7.25, 5.2% glucose showed a significant decrease in streaming potential (P <0.001). these results show that changes in temperature and storage medium markedly affect the streaming potential (electrokinetic properties) of bone in vitro.