Effects Of Mixed Exposure Of Methyl Parahydroxybenzoate And Ethyl Parahydroxybenzoate On Reproduction And Offspring Of Female Fruit Flies

Parabens are a group of alkyl esters of p-hydroxybenzoic acid(PHBA),because of its antibacterial properties,it is widely used in daily products such as toothpaste,hair/shaving products,cosmetics,food,medicines,food packaging and industrial products.The extensive use of parabens also exposes humans to all aspects including food,clothing and the environment.A growing number of studies have shown that parabens are a class of endocrine disruptors,it can have adverse effects on animal reproduction and cause controversy over the use of such substances.Although existing in vitro and in vivo studies have shown that there is a weak estrogenic effect of parabens.However,due to the limitation of research institutes,the possible estrogenic hazards are still unclear.It is necessary to further study its reproductive toxicity and further determine the effect of paraben exposure on reproduction.In addition,parabens are often used in combination to have better antiseptic effect.Therefore,it is more urgent and more realistic to carry out the experiment of mixed parabens exposure.In this study,Drosophila melanogaster(Canton-S strain)was used as the experimental material,and methylparaben(MP)and ethyl ester(EP)commonly used in parabens were mixed in a mass ratio of 1:1(MP+EP).The effect of MP+EP on the reproduction of the female Drosophila was analyzed from the physiological level and the molecular level by exposing the newly emerged female Drosophila in different concentration groups and different days.This research set the control group and three MP+EP concentration groups(300 mg·L-,700 mg·L-1,1000 mg·L-1),exposures on different days(5 d,10 d,15 d,20 d,25 d).At the physiological level,we calculated the parental and offspring fertility,and calculated the offspring deuteration rate,emergence rate,growth cycle.At the molecular level,we used qRT-PCR to detect the expression of reproductive-related genes in the parents and offspring.The results of the study are as follows:(1)Newly emerged parental female Drosophila have been exposed,the parental 300 mg·L-1 group had an estrogenic effect and promotes spawning,also fertility increased compared to the control group.However,the parental 700 mg·L-1 and 1000 mg·L-1 groups have toxic effects that affect spawning,also fertility decreased compared with control.The total number of eggs laid in the offspring concentration group was lower than that in the control group,and the fertility was reduced.This shows that the toxicity of hydroxyphenyl esters may be transmitted to offspring through reproductive methods,but it needs to be further studied.The total number of eggs spawned by the parent is smaller than that of the offspring,and the parental fertility is more affected by the exposure.In addition,as the number of exposure days increases,the fertility of the parental and offspring varies.This shows that the effect of hydroxyphenyl ester varies due to different exposure days.(2)Newly emerged parental female Drosophila have been exposed,it affects the deuteration rate,the emergence rate,and the growth cycle of offspring.Compared with the control group,the deuteration rate was significantly reduced in the three concentration groups.For the emergence rate,the emergence rate of the 300 mg·L-1 group decreased slightly,while the 700 mg·L-1 and 1000 mg·L-1 groups decreased significantly.Exposure to different days,the deuteration rate and emergence rate of the concentration group have different reductions compared to the control group.In addition,the progeny egg-pupa and egg-adults growth cycles were extended in the concentration group.And the duration of egg-adults in the 700 mg·L-1 group was significantly prolonged.The progeny growth cycle also has different degrees of prolongation with increasing exposure days.It can be seen that the parental exposure affects the development of offspring,and prolonging the growth cycle of offspring may be an adaptation to the exposure.(3)Newly emerged parental female Drosophila have been exposed,it affects the expression of reproductive-related genes(LnR,AKT,TOR,YPR)in both parental and offspring.The expression of LnR,AKT and TOR genes in the concentration group was higher in the offspring than in the parent.However,YPR gene expression is contrary to the other three genes.With the increase of exposure days,the expression of LnR,AKT,TOR and YPR genes showed fluctuating changes.This suggests that MP+EP affects the reproduction of female Drosophila through disordered reproduction-related gene expression.Comprehensive knowledge of the experimental results,female Drosophila parent exposed to MP+EP,there will be varying degrees of influence on the parental reproductive and offspring reproductive or development.Parabens function differently in different concentrations,the 300 mg·L-1 group has an estrogenic effect and increased fertility.However,toxic effects were observed in the 700 mg·L-1 and 1000 mg·L-1 groups,with reduced fertility and delayed development.In addition,the role of hydroxyphenyl esters varies with the number of exposure days.This indicates that it may affect reproduction through affecting the nutritional signaling pathway,but the mechanism of action needs to be further explored.