Study On The Toxicity Mechanism Of Microcystis Aeruginosa To Zebrafish

With the aggravation of water eutrophication around the world,cyanobacteria bloom-forming frequently occur in freshwater and marine ecosystems and its harm should not be ignored.As the victims which are exposed to algal blooms directly,aquatic organisms may be at higher health risk than terrestrial organisms.In recent years,the toxicological effects of a single cyanotoxin has been well documented in aquatic organisms,and one of the most studied is microcystins(MCs).Therefore,in order to make realistic evaluations of toxicity of algal blooms to fish,we assessed the hepatotoxicity,reproductive and endocrine systems of adult zebrafish and the developmental neurotoxicity on newly hatched zebrafish induced by Microcystis aeruginosa(M.aeruginosa).The results showed as follows,(1)after exposure,marked histological lesions in the liver or gonads,such as nuclear pyknosis and deformation,were observed.The pp activity were decreased significantly in the treatment.The result of the proteomic analysis showed that the expression of the protein was affected by the M.aeruginosa.(2)The fertilization rate and hatchability of eggs spawned from treated females were both significantly lower than they were in females in the control group.Moreover,M.aeruginosa exposure decreased the concentration of 17?-estradiol(E2)and testosterone(T)in female zebrafish.(3)After 96 hours of exposure,the locomotor activity of zebrafish larvae was significantly decreased with increasing algae concentration.The levels of both acetylcholinesterase and dopamine were decreased,accompanied by a decline in ache,chrna7 and manf and a compensatory increase in nr4a2 b transcription.Furthermore,the expression of nine marker genes for nervous system function or development,similarly decreased after algal exposure.Those results suggesting that M.aeruginosa could damage to hepatic function,disrupt the reproductive and endocrine system and damage to the nervous system,which highlight the necessity for further investigation of cyanobacterial bloom mixtures when assessing the ecotoxicity of cyanobacteria.