Effect of heat stress on heat shock protein 30 (Hsp30) mrna expression in rainbow trout (oncorhynchus mykiss)

Abstract

Rainbow trout (Oncorhynchus mykiss) is a cold-water species, and often affected by high temperatures. To understand hsp30 mRNA expression trend and molecular mechanism responding to high temperature stress, real-time qPCR was used to quantify hsp30 mRNA expression level in different tissues (heart, liver, gill, brain, spleen and head kidney) in control (18°C) and heat-stressed (25°C for 2, 4, 8 and 12 h) groups. Results showed that hsp30 mRNA in all tissues had already synthesized at 18°C. hsp30 mRNA expression in all tissues was significantly up-regulated and reached the peak after heat stress at 25°C for 2-4 h (P<0.05), then significantly down-regulated at 8 h (P<0.05), and finally returned to control level at 12 h and HSR (P>0.05). The highest hsp30 mRNA expression levels were recorded in heart and liver after 2-4 h. However, the most significant changes of hsp30 mRNA after 2-4 h were observed in gill by 15668.243- and 11452.125-fold compared with 18°C. These results indicated that hsp30 mRNA expression in rainbow trout was induced by heat stress and responded in a time- and tissue-specific manner. Hsp30 can provide some protection in heat stress, but it is only within a certain range.