Mechanisms Of Cannabinoid Receptor 1 In Reproductive Toxicity Induced By DBP Exposure In Male Rats

Objective:To explore the general toxicity of reproductive system damage in male rats exposed to dibutyl phthalate(DBP)and the expression and mechanism of cannabinoid receptor 1(CBR1)in reproductive damage.Methods:Construction of SD male rats model: Rats were randomly divided into 4 groups,including control group and low,medium and high dose groups(DBP 100 mg/kg,250 mg/kg,500 mg).After 28 days of continuous gavage,the animals were anesthetized.Weigh both testes and epididymis and calculate their organ coefficient.The sperm motility parameters of the mice were detected by CASA system: sperm motility and density.Sperm morphology was observed under light microscope after staining with eosin.HE staining and transmission electron microscopy were used to observe the changes of testicular tissue structure and ultrastructure of sperm cells.Enzyme-linked immunosorbent assay(ELISA)was used to detect serum reproductive hormones,including testosterone(T).,estradiol(E2),luteinizing hormone(LH),follicle stimulating hormone(FSH)and sex hormone binding protein(SHBG);Western blot analysis of spermatozoon transmembrane cells such as p38,ERK,AKT The key molecules on the signal transduction pathway and the protein expression of CBR1 were detected by qRT-PCR for mRNA expression of the above related genes.Results:1.Compared with the control group,the DBP 500 mg/kg treatment group had statistically significant differences in body weight and testicular organ coefficient;compared with the control group,DBP(100 mg/kg,250 mg/kg,500 mg/kg)treatment group was larger.The sperm motility and sperm motility of the rats were significantly decreased,while the sperm density of the 500 mg/kg DBP treatment group was significantly decreased(P<0.05);there was no significant difference in sperm deformity rate;2.Compared with the control group,the serum testosterone level of the male rats in the DBP treatment group was significantly decreased(P<0.05),and the serum SHBG level in the 500 mg/kg male rats was significantly increased(P<0.05);The serum levels of E2 and LH in the DBP exposed group were significantly lower(P<0.05).On the other hand,the serum FSH level increased significantly(P<0.05).3.Compared with the control group,the testicular seminiferous tubules of the 250mg/kg and 500mg/kg DBP treatment groups were damaged,the spermatogenic cells were arranged disorderly,and the large lumen and the official cavity showed obvious sperm reduction;DBP(500mg/kg)The spermatogenic cells of the group support the morphological changes of the cells and the interstitial tissues are reduced;4.Compared with the control group,at the molecular level,CBR1 and ERK were up-regulated with increasing DBP dose,while p38 was down-regulated with increasing dose.These protein expressions were dose-responsive with DBP exposure.Relationship;the expression levels of p-p38 and p-ERK in the activated forms of p38 and ERK were down-regulated;5.Compared with the control group,at the genetic level,the expression levels of these key molecules CBR1,p38 and ERK were consistent with their expression at the protein molecule level.Conclusion:We found that the DBP treatment group(100 mg/kg,250 mg/kg,and 500 mg/kg)caused a significant decrease in sperm motility,a disordered serum reproductive hormone level,and a change in testicular pathology even at lower doses.Its possible mechanism: DBP exposure can up-regulate the expression of CBR1 in testis tissue,and may regulate the proliferation and differentiation of spermatogenic cells and the synthesis and secretion of testosterone in spermatogenesis through ERK and p38 MAPK signaling pathways.Provide a new theoretical basis and feasible intervention for the impact of environmental pollution PAEs exposure on male reproductive health.