Study On The Lesions And Expression Of HSP70 MRNA In Heat Acipenser Schrenckii

Stress can cause stress disease of animals and result in various degree of economic loss.In this study,Acipenser schrenckii were stressed with 32℃ warm water,the morphologic changes,the blood biochemical indices and the expression of HSP70 mRNA in tissues of heat stressed A.schrenckii were studied,and the purpose was to provide scientific evidence to diagnosis of stress disease of A.schrenckii.A.schrenckii(45)were divided into control group A and experimental groups B,C,D four groups,these A.schrenckii.were raised in circulating water(18±1.0℃)for 48 h,stressed with 32℃ warm water for 0,2,4,6 hours,respectively,euthanatized with eugenol and serum specimens were collected for detection of blood biochemical indices,including total protein(TP),albumin(ALB),globulin(GLO),creatinine(CRE),urea nitrogen(UN),glutamic oxalacetic transaminase(AST),glutamic pyruvic transaminase(ALT),lactic dehydrogenase(LDH),and malondialdehyde(MDA).Then A.schrenckii were necropsied,gross lesions were observed.Muscle,heart,intestine,and other tissues were collected and fixed in 10%formalin,the histologic changes were observed in paraffin-embedded,hematoxylin and eosin-stained sections.The heart,liver,and spleen were collected and used to detect the expression of HSP70 mRNA by means of real-time qPCR.The results indicated that:(1)Grossly,the morphologic changes included hyperemia in body surface and several visceral organs,especially in fin,abdomen and intestine,prominent hemorrhage in fat within the peritoneal cavity.The colour in hyperemic sites became black gradually with stress time.Histologically,hyperemia and melanin deposition were seen in heart,liver,kidney,stomach,intestines,brain,subcutaneous tissue,gills,fins,esophagus and fat.Eosinophils were increased significantly in heart,liver and ileum.Degeneration and necrosis of muscle fibers were observed in subcutaneous tissue,heart,stomach and fins.(2)After heat stress,all blood biochemical indices increased gradually at first and then decreased.The content of serum ALB reached the highest at 2 h(8.20±0.39 g/L)after heat stress,there were highly significant differences between the experimental and control groups(P<0.01);The serum TP,GLO,AST,ALT,UN,MDA reached the highest at 4 h after heat stress,the contents were 21.34±0.62 g/L,15.67±0.50 g/L,1159.45±40.22 IU/L,98.72±8.87 IU/L,0.69±0,04 mmol/L and 10.49±0.43 nmol/ml,respectively.there were significant differences between the experimental groups and control groups(P<0.05);The serum CRE and LDH reached the highest at 4 h,2 h,respectively,no significant difference were found between the experimental groups and control groups(P>0.05).These findings suggest that serum TP,ALB,GLO,AST,ALT,UN,MDA may be of diagnostic significance to heat stress of A.schrenckii.(3)Normally,the relative expression quantity of HSP70 mRNA in the tissues of A.schrenckii was liver,followed by spleen,heart,brain,kidney,muscle and intestine,so liver,spleen and heart of all groups were collected to detect the relative expression quantity of HSP70 mRNA.Results showed that the relative expression quantity of HSP70 mRNA increased gradually with heat stress time,significant differences(P<0.05)or highly significant differences(P<0.01)were observed between experimental groups and control group.It was possible to conclude that significant lesions presented in heat stressed A.schrenckii,characterized by hyperemia of body surface,degeneration and necrosis of muscle fibers,increase of eosinophils and melanin deposition.The contents of serum ALB,GLO,TP,AST,ALT,UN,MDA increased.The relative expression quantity of HSP70 mRNA in liver,spleen and heart increased in heat stressed A.schrenckii.