Font Size: a A A

Study On The Reproductive Toxicity Mechanism Of Ethyl Paraben On Male Drosophila Melanogaste

Posted on:2023-03-13Degree:DoctorType:Dissertation
Country:ChinaCandidate:Y WangFull Text:PDF
GTID:1520306824489424Subject:Genetics
Abstract/Summary:PDF Full Text Request
Parabens is widely used as a preservative because of its wide spectrum of antibacterial activity,and ethylparaben(EP)is the most widely used food additive.Due to the mass production and use of parabens,its pollution to the environment and exposure to organisms has become a worldwide safety problem.Combined with the research status at home and abroad,a large number of literatures have reported that parabens can affect the reproductive system and neural development of organisms,but many problems on human health have not been explained.Transcriptome analysis revealed that EP exposure in male Drosophila melanogaster down-regulated the expression of α-Mannosidase(α-Man)related gene Lysosomal alpha-mannosidase IV(Lman IV,also known as CG9465)in Drosophila melanogaster.α-Man is a rate-limiting enzyme and landmark protein in energy metabolism network.Its activity is closely related to sperm capacification and acrosome reaction.However,the mechanism of parabens affecting α-Man gene expression has not been reported.Based on our previous transcriptome analysis results and combined with literature,we speculated that EP may down-regulate LMan IV expression through G protein alpha i subunit(Gαi)—Protein kinase A(PKA)—Target of rapamycin(TOR)signaling pathway(Gαi-PKA-TOR)mediated by G protein-couple receptors(GPCRs).By microscopic examination,quantitative RT-PCR(q RT-PCR),ultraviolet absorption spectroscopy and enzyme-linked immuno sorbent assay(ELISA),the expression regulation and functional indexes of α-Man gene and male Drosophila exposed to EP were detected at morphological,physiological,cellular,protein and gene levels,and the data were statistically analyzed to explore the mechanism of EP on male Drosophila reproductive toxicity and progeny development.To provide data support for the safety application of EP as food additive.Specific research results are as follows:1.According to the results of acute toxicity test of EP to male Drosophila,the lethal concentration of 50%(LC50)was 15603 mg/L(95% confidence interval,FL was12624 mg/L to 19.418 mg/L),and the lethal time of 50%(LT50)was 9.957 d(95%confidence interval,FL was 9.070 d to 11.098 d),the exposure concentration of EP on male Drosophila reproductive toxicity was set as 1500 mg/L,750 mg/L and 375mg/L;The exposure time was 9 days.2.Reproductive toxicity of EP to male D.melanogaster:(1)EP has reproductive toxicity to male D.melanogaster and affects progeny development cycle;(2)With the increase of the concentration of EP,the reproductive toxicity showed toxicity stimulation effect.3.The octopamine receptor signaling pathway regulates the reproductive toxicity of EP on male Drosophila:(1)by regulating the expression of LMan IV in male Drosophila,α-Man activity is affected,resulting in reproductive dysfunction;(2)By regulating protein kinase,c AMP-dependent,catalytic subunit 1(Dco)expression in male Drosophila,PKA activity was affected,and sperm viability and activity level were affected;(3)The dose-response curves of the Tyramine/Octopamine receptor(Oct/Tyr R)-EP and α-Adrenergic-like receptor(OAMB)-EP were U-shaped,indicating that EP had Hormesis-effect on male D.melanogaster;(4)The conjugation of EP with albumin increases the possibility of receptor desensitization;(5)EP is a potential agonist of oct/tyr R and oamb.EP activates Protein kinase C(PKC)signal transduction pathway and upregulates LMan IV expression through Oct/Tyr R,while the later down-regulation of LMan IV expression is related to Oct/Tyr desensitization and OAMB activation.4.H3K27me3 may regulate the reproductive toxicity of EP on male Drosophila and its progeny development by desensitization of Oct/Tyr R and OAMB receptors.EP has Hormesis-effect on male Drosophila reproductive capacity,and its molecular mechanism is caused by EP regulating Oct/Tyr R and OAMB receptor desensitization through H3K27me3.In the future,CHIP-seq can be used to further explore the epigenetic regulation of GPCRs signaling pathway in EP-exposed male Drosophila.This study may lay a theoretical foundation for the rational application of parabens,and to provide data support for the safety evaluation of these substances.
Keywords/Search Tags:Ethylparaben, Male Drosophila melanogaster, Reproductive toxicity, Hormesis-effect, Receptor desensitization
PDF Full Text Request
Related items