A parametric study of freezing injury in ELT-3 uterine leiomyoma tumour cells

Cellular level freeze injury was investigated after controlled freezing of an Eker rat uterine fibroid cell line in both the presence and absence of o estradiol. The connection between thermal history and cell injury in single ELT-3 cells in suspension (without oestradiol) was studied through a two-l evel, four-parameter (2(4)) experiment with membrane dye exclusion as the e nd-point. The four parameters considered were cooling rate (CR), end temper ature (ET), hold time (HT) and thawing rate (TR). A high and low value of e ach parameter was selected as follows: CR, 5-25 degreesC/min; ET, -20 to 30 degreesC; HT, 0-5 min; TR 20-200 degreesC/min. The greatest parameter effe ct on freeze injury in this range was ET followed by HT, then TR and finall y CR. In addition, significant parameter interactions and curvature were fo und. Additional CR results outside the original parameter range showed a re duction in survival at both 1 and 50 degreesC/min suggestive of an inverted U-shaped survival curve. These results show that this tumour system is sus ceptible to cryoinjury, particularly at temperatures below -30 degreesC wit h HT of >5 min and slow thawing. In addition, the presence of oestradiol wa s found to increase the susceptibility of these cells to cryoinjury.