Various Toxic Effects And Mechanism Of Dexamethasone On Caenorhabditis Elegans

Objective:In this paper,we used simulated animal Caenorhabditis elegans(C.elegans)infiltration with different concentrations of dexamethasone dilution for a certain period of time,and observe the changes in physiological level(life span,reproductive ability,exercise behavior),biochemical level(apoptosis)and molecular level(partial stress gene expression)of C.elegans.Finally to explore the toxic effects of dexamethasone on nematodes and infer the mechanism of action of dexamethasone Methods:The K-medium solution was used to configure the dexamethasone dilution,and C.elegans was exposed to 500,1000,1500,and 2000 mg/L dexamethasone solution respectively.At the same time,a blank control group(0mg/L)of K-medium solution was established.After exposing the nematode liquid for 48 h,observe and record the lifespan,growth and development,reproduction and exercise behavior of C.elegans under a stereo microscope;Acridine orange AO staining was used to protect C.elegans after exposure to liquid for 2h,and the apoptosis of C.elegans was observed under a fluorescent inverted microscope;The total RNA of C.elegans after liquid exposure was extracted,and the molecular expression of some stress-related genes of nematodes was detected by real-time fluorescent quantitative PCR using Japanese TAKATA kit.Results : Compared with the blank control group(0mg/L),the dexamethasone-exposing groups of C.elegans have:(1)The longevity and average lifespan of C.elegans declined slightly,but there was no significant difference(P> 0.05).(2)The number of offspring of C.elegans and the number of eggs in the uterus decreased to varying degrees.Among them,the number of nematode offspring in the 1500 mg/L and 2000 mg/L experimental groups decreased significantly(P <0.05),The number of nematode uterine pregnant eggs in the experimental groups of 1000,1500 and 2000 mg/L decreased significantly(P<0.05).And all have concentration-dose effects,indicating that dexamethasone has potential reproductive toxicity effects.(3)The nematode’s ability to exercise has decreased to varying degrees.Among them,the frequency of nematode head swing in the 1500 mg/L and 2000 mg/L experimental groups decreased significantly(P <0.05),In the experimental groups of 1000,1500 and 2000 mg/L,the nematode body bending frequency and pharyngeal pump beat frequency decreased significantly(P<0.05),it also has a certain dose-effect relationship.Comparing the different sports behavior indexes of the same concentration group,the sensitivity to drug exposure is: body bending>Throat beating>head swing,indicating that dexamethasone has a potential neurotoxic effect.(4)The apoptosis of nematodes in each experimental group has increased to a certain extent.Among them,the relative fluorescence intensity of nematodes in the 1500 and 2000 mg/L experimental groups increased significantly(P <0.05),and the apoptosis increased.This suggests that dexamethasone may cause toxic effects of physiological behavior changes by increasing apoptosis in the nematode.(5)The expression levels of some stress-related genes in the nematode were detected by real-time quantitative PCR.When compared with the blank control group(0 mg/L),It was found that dexamethasone exposure caused a significant increase in the expression of superoxide dismutase gene(sod-1),The expression of glutathione transferase gene(gst-1)is significantly reduced,The expression level of P-53-like protein gene(cep-1)was significantly up-regulated and then decreased significantly.The expression of cytochrome P450 gene(cyp-35a2)and aging-related protein gene(age-1)are slightly different.It is suggested that dexamethasone may cause nematode growth and development toxic effects through the oxidative stress pathway and at the same time interfere with the mechanism of detoxification in vivo.Conclusion : Dexamethasone is potentially reproductive and neurotoxic to C.elegans.High concentration of dexamethasone can significantly inhibit the nematode’s ability to reproducetion and exercise,and these toxic behavior changes has a dose-concentration dependence.High concentration of dexamethasone will aggravate the process of C.elegans cell apoptosis.Based on the expression of some stress-related genes,Caenorhabditis elegans can respond to and resist the stress caused by low concentrations of dexamethasone,but it cannot resist high concentrations of dexamethasone.It is suggested that the oxidative stress mechanism is the main mode of action of dexamethasone causing nematode toxic effects,and Dexamethasone also interferes with the normal detoxification mechanism in the nematode,resulting in stress on the nematode caused by the stress environment.