Study On Toxicity Of Hippocampal Formation Induced By Formaldehyde And The Corresponding Rescue Effect Of Astaxanthin In Mice

After entering the 21 st century,people are gradually improving their the quality of life and their needs.Interior decoration has become the mainstream of most families.The study shows that: the degree of outdoor air pollution is far less serious than indoor air pollution,which results in many diseases.FA(Formaldehyde,FA)is the major cause of indoor air pollution.Renovation nowadays has become the main source of FA nowdays.Due to the relatively closed living conditions of modern people,once the new house is renovated,the generated gaseous FA is difficult to be drained and further reduce the indoor air quality.And indoor FA international standard is 0.1mg/m3.According to the survey,the FA concentration after renovation of new homes can be as high as 0.5 mg /m3,five times as the international standard concentration,and some can even reach the working environment of certain occupational exposure concentrations.People spend more than 90% of the time in the room,so the FA hazard has become a hot spot in the society of today.Learning and memory and cognitive functions are mainly involved by the limbic system,which is dependent on the cerebral cortex and hippocampal formation.As the brain is rich in phospholipids,phospholipids contain a large number of iron ions that catalyze the production of ROS(Reactive oxygen species,ROS)and are highly susceptible to oxidative damage.FA inside the brain tissue may result in the ability to eliminate reactive oxygen species of ROS decreased,resulting in excessive accumulation of ROS in the cell membrane and afterwards caused by the performance of brain tissue oxidative damage.Experiments show that the increase of FA can cause the changes of superoxide dismutase(SOD),malondialdehyde(MDA)and glutathione(GSH)to further lead to the increase of oxidative damage.In the FA-exposed mice,mitochondria were swollen,separated and broken,and vacuolar changes were observed,indicating certain damage to nerve cells.Meanwhile,FA was found in some neurodegenerative diseases were found,indicating that FA has a very serious impact on oxidative damage.AST(Astaxanthin,AST)is one of the most potent natural anti-oxidants.Its unique structure allows it to capture free radicals,destroy the chain of superoxide and interrupt the oxidation process,thus effectively removing ROS and preventing other molecules and tissue cells injury,as AST has super antioxidant capacity.Therefore,AST performs significant therapeutic and neuroprotective effects in many clinical applications of degenerative diseases.In this study,we perform intraperitoneal injection of FA to simulate the status of formaldehyde poisoning,and since AST can be traced to across the blood-brain barrier with strong anti-oxidation,anti-inflammatory properties,the method of intragastric administration of AST treatment,Compared with the past treatment of FA poisoning,our proposed therapy is more innovative and may open up a new way for the future development of AST new treatment.Materials and Methods 1.Establishment of animal model and grouping Animal model establishment and grouping: In this experiment,we use 40 Liaoning longevity Kunming male mice.The rats were randomly divided into 4 groups: CON(Blank control group,n = 10),FA(Exposure to formaldehyde,n = 10),AST(Astaxanthin alone group,n = 10)and FA+AST(treated with formaldehyde and astaxanthin,n = 10),The FA group was intraperitoneally injected with 20mg·kg-1d-1 FA intraperitoneally(20mg·kg-1d-1)for 7 days.The FA+AST group was meanwhile injected with FA followed by 30 days of intragastric administration of AST treatment.After gavage treatment,the materials of BDNF and SYN were observed and monitored in hippocampus 2.The test of Morris water maze behavioral test On the second day after intragastric administration of astaxanthin,Morris water maze test was performed on the second day of the four groups of mice.Navigation location the navigation experiment is to avoid the incubation period when the animal finds the platform within 60 seconds.On the 7th day,a space exploration experiment was started.After the underwater platform was removed,the number of times that the four groups of mice passed through the original platform position within 60 seconds was recorded.3.Immunohistochemistry specimen preparation staining method Observation of SYN and BDNF in two learning and memory abilities of neruons in CA1 and CA3 of hippocampus was performed by immunohistochemistry.4.Western blotting We determined the two protein SYN and BDNF expression in the hippocampal formation of the specific circumstances.5.The statistical analysis The above data were expressed as mean ± standard deviation(x—±s),using SPSS 20.0 software for statistical analysis,and within the four groups of SYN and BDNF protein were compared,using the Studet’s t test statistical analysis,Within group comparison was applied by one-way ANOVA,P <0.05 had statistical significance.6.Conclusion In this study,Morris water maze behavior test,immunohistochemistry staining and Western blotting were used to prove that astaxanthin can regulate the expression of hippocampal synaptic plasticity protein SYN and learning-memory-associated protein BDNF,thus improving the appearance of formaldehyde in neurons exposed to formaldehyde and achieve its effect on antioxidant and anti-formaldehyde toxicity.