Effects of High-Energy Shock Waves on Rapidly Proliferating Cells: African Clawed Toad ( Xenopus laevis ) Zygote Model

Abstract

To date few studies have described the effects of high-energy shock waves (HESW) on benign, rapidly proliferating cells. In the African clawed toad (Xenopus laevis) model, previously described in vitro fertilization methods were used to study the effects of HESW on zygote cleavage and blastocytosis. Groups of 50 freshly fertilized ova were placed at the bottom of clear ultracentrifuge tubes filled with 5% DeBoers solution, positioned at the f2 focus utilizing the biprismatically split halogen red laser of a Dornier XL-1 experimental lithotripter, and treated using an 80-nF capacitor at various kilovoltages and shock wave (SW) numbers. Controls were treated in an identical fashion but kept outside the f2 focus. Cell lysis was the most notable finding at power settings in the standard treatment range (12 kV or greater). Increasing kilovoltage at a constant SW number (100) correlated linearly with the number of zygotes lysed in each group. There was an apparent logarithmic decrease in progression to cleavage and early development with increasing kilovoltage. At 10 kV, no effect on development was observed. Increasing SW numbers at a constant 19 kV correlated linearly with an increase in the number of lysed zygotes in each group. Increasing the SW number at constant kilovoltage correlated with an apparent logarithmic decrease in progression to cleavage and early development. This effect was observed with as few as 10 SW. These experiments have demonstrated a correlation between viability and lysis of zygotes with increasing treatment energies. The data suggest a threshold setting that minimally affects cellular activity (10 kV). Also, the results support the hypothesis that rapidly proliferating tissues suffer irreversible consequences from the application of HESW.