Effects Of A Mixture Of Methyl And Propyl Parabens On Lifespan, Antioxidant Capacity, And Apoptosis In Drosophila

P-hydroxybenzoic acid esters,also known as parabens,have the advantages of br oad-spectrum antibacterial properties,high efficiency and low toxicity as preservatives,and are widely used in personal care products,cosmetics,food,Health products and pharmaceuticals.Methylparaben(MP) and propylparaben(PP) are used most frequently.Studies have found that parabens have an estrogen effect,and as endocrine disruptors,they affect the growth and development and the reproductive system of organisms.In this study,wild-type Drosophila melanogaster was used as experimental material.D.mel anogaster was exposed through a mixture of MP and PP(mass ratio 1:1),and its effec ts on lifespan,antioxidant capacity and apoptosis of D.melanogaster were discussed.D.me lanogaster was exposed to 0mg/L(control group)and concentration groups of 300mg/L,700mg/L,and 1000mg/L of mixed esters of MP and PP.The survival rate of newly emerged male and female D.melanogaster was measured,and the average lifespan,maximum lifespan and half death time were calculated.D.melanogaster t reated with MP and PP for 1d,5d,15d,20d,and 25d were selected to test their SOD,C AT,GST activity and MDA content.The midgut of female D.melanogaster was dissected to make a cell suspension,and the DNA damage was detected by single cell gelelectr ophoresis(SCGE).The tail length(TL),relative DNA content in the tail(TD),relative DNA content in the head(HD),and Olive tail moment(OTM)were analyzed by Casp software.QRT-PCR was used to detect the relative expression levels of proapoptotic genes reaper,Debcl and apoptosis inhibitory genes Diapl and Buffy.Draw the following conclusions:(1)The survival rate of male and female fruit flies showed a downward trend after MP and PP mixed exposure.The number of female flies in the 300mg/L concentration group began to decrease rapidly after 25 d,while the 700mg/L and 1000mg/L concentration groups showed a rapid decline at10-20d.The decline in the survival curve of male flies is more severe than that of female flies.The decreasing trend of the concentration group accelerated at 15d.The average lifespan,half death time,and maximum lifespan of male and female D.melanogaster were significantly shortened.Among them,the average life expectancy of female flies was shortened to 60% of the control group,and male flies was shortened to 54%.(2)The activity of SOD and CAT in male and female D.melanogaster showed a trend of first increase and then decrease after mixed exposure of MP and PP.It was higher than the control group at 1d and 5d,and the activity of SOD and CAT at 700mg/L and 1000mg/L group decreased at 10d.GST vitality began to decrease signifi cantly at 5d.MDA content in male and female flies increased significantly,and the 1000mg/L group reached the maximum at 25d.(3)DNA damage becomes more severe with increasing days and concentrations.In the 300mg/L group,the degree of damage began to increase at 20d,and TD increased,showing mild damage.The 700mg/L group was mildly injured at 1d and 5d,and the TL and OTM increased with time,and moderate damage was observed at 10d.The 1000mg/L group showed a high degree of injury at 25d,and the TD value reached 43.26±1.46%.(4)The relative expression levels of proapoptotic genes reaper and Debcl in D.melanogaster were up-regulated after treatment with mixed esters of MP and PP.In female flies,the relative expression of Debcl increased in the 300mg/L group at 5d and15d,700mg/L grou p reached the maximum at 10d.The relative expression levels of1000mg/L male flies increased at 5d,10d,15d,and 20d.The relative expression of reaper was the highest at 10d in the 1000mg/L female flies group,and the relative expression of reaper in males was higher than that in females after treatment.The relative expression levels of apoptosis-inhibiting genes Buffy and Diap1 were down-regulated in both male and female D.melanogaster,and their ability to inhibit apoptosis was weakened,which promoted the occurrence of apoptosis.In summary,parabens cause an increase in lipid peroxidation in D.melanogaster cells,leading to an increase in MDA content,inhibition of SOD,CAT,and GST antioxidant enzyme activities,causi ng DNA damage to midgut cells and inducing apoptosis.This study provides data to further evaluate the safety of parabens.