Meeting Abstract

3.11  Wednesday, Jan. 4  Rainbow trout Oncorhynchus mykiss erythrocytes respond to thermal stress in vitro PLANT, K.P.; POWELL, M.S.; RODNICK, K.J.*; HARDY, R.W.; University of Idaho, Hagerman; University of Idaho, Hagerman; Idaho State University, Pocatello; University of Idaho, Hagerman kplant@uidaho.edu

Fish erythrocytes can be long-lived and carry out gene expression and protein synthesis during their lifetime. In fish, erythrocytes likely compensate in predictable ways, by either up-regulation or down-regulation of specific genes in response to physiological stressors. In this study, blood was sampled from rainbow trout maintained at 14-15°C, transferred to dialysis cassettes and incubated in modified Cortland’s saline and citrate phosphate dextrose adenine (CPDA). After acclimation to the Cortlands-CPDA buffer at 14°C the cassettes were transferred to Cortlands-CPDA at 27°C for 2 h and subsequently transferred back to 14°C for 48 h. Control blood remained at 14°C for 48 h. Blood was sampled for RNA extraction prior to heat shock and 1, 4, 24 and 48 h post heat shock. Blood smears were carried out prior to heat shock and 24 and 48 hours post heat shock to verify cell condition. Real time PCR was used to measure mRNA expression of a selection of heat shock, apoptosis, REDOX and mitochondrial genes along with glucose transporters. Results indicated heat shocked erythrocytes had significantly elevated levels of heat shock protein (hsp) 70 mRNA at 1 - 4 h post treatment, unlike control erythrocytes. Hsp70 levels peaked at 1 - 4 h post heat shock and decreased over time demonstrating a significant response to the treatment. Likewise GLUT1 transporter expression increased more rapidly in heat shocked cells in comparison to erythrocytes that remained at the control temperature. Histological examination of erythrocytes did not show physical changes in erythrocytes between treatment and controls.