| BackgroundEthephon(2-chloroethylphosphonic acid;Ethrel)is a common low-toxicity plant growth regulator that can affect the expression of plant flower sex,promote plant fruit ripening,induce plant organ shedding,etc.Studies have found that ethephon is harmful to the growth and development of animals,especially to the reproductive system.However,studies on the reproductive toxicity of ethephon are still rare.In order to explore the effects of ethephon on the reproductive system of offspring rats,we designed this experiment.ObjectiveTo investigate the effect of ethephon on the testis pathological structure,apoptosis of spermatogenic cell and Sex hormone level in offspring male Rats.To explore the mechanism and manifestation of ethephon on reproductive toxicity of offspring rats,and provide a theoretical basis for the safe application of ethephon and the prevention of childhood growth and development diseases.Methods24 healthy female SD rats of 45 days old were randomly divided into control group,low-dose ethephon group,medium-dose ethephon group and high-dose ethephon group according to body weight.Selected male rats of the same age to mate with female rats.The rats were fed ethephon solution of different concentrations or normal saline(9g/L)every day,and they were continued to be fed during pregnancy and lactation.At the age of 7 days and 14 days,10 offspring male rats were randomly selected from each group and were put to death.The testicular tissue was stained with HE,the morphological changes of the testis were observed with light microscope;the apoptotic cells were labeled with erminal deoxynucleotidyl transferase dUTP nick end labeling(TUNEL method)and the apoptosis index of testis spermatogenic cells was detected with fluorescence microscope.The levels of serum luteinizing hormone(LH),testosterone(T),follicle stimulating hormone(LH)and estradiol(E2)were measured by chemiluminescence immunoassay.Data were expressed as mean values ± SE,and statistical analysis was performed using one-way ANOVA followed by Bonferroni’s multiple comparisons test as post hoc test to determine the significant differences among means.These differences were analyzed at the 5% probability level(P value <.05 was considered statistically significant).Results1 When the rats are 7 days old and 14 days old,the testicular mass of the high,medium and low dose ethephon group was lower than that of the control group,and the difference was statistically significant(all P values <0.05).The testicular mass of the rats in the same experimental group gradually increased during the growth period.The testicular mass of the 14-days-old rats in the control group and the low-dose ethephon group was significantly higher than that in the 7-days-old rats.(P<0.01),and The weight of testes in the 14-days-old offspring of the middle-dose ethephon group and the high-dose ethephon group was higher than that of the testis of the 7-days-old offspring rats.(P<0.05).2 At the age of 7 days,the testis internal structure of the control group developed well,and the spermatic tubules were neatly and compactly arranged.In the low-dose ethephon group,the seminiferous tubules of the testis were slightly smaller and the spermatogenic cells were loosely arranged compared with the control group.In the midium-dose ethephon group,the testis seminiferous tubules were slightly disordered and the cell gap increased.In the high-dose ethephon group,the testis development was poor,the diameter of seminiferous tubules decreased significantly,and the spermatogenic cells arrangement were in disorder.At the age of 14 days,The testis of the control group developed well,and the diameter of the seminiferous tubules increased significantly compared with 7 days old.The testicular development of each experimental group gradually decreased with the increase of ethephon concentration.3 At the age of 7 days,there was no statistically significant difference in spermatogenic cell Apoptotic Index(AI)between the low-dose group [(0.54±0.10)%] and the control group[(0.53±0.09)%](P>0.05),while the spermatogenic cell AI in the medium-dose ethephon group [(0.63±0.11)%] and the high-dose ethephon group [(0.81±0.06)%] are higher than that in the control group,thus there exists a statistically significant difference(all P values<0.01).The spermatogenic cell AI in the low-dose ethephon group [(0.54±0.10)%] is lower than that in the medium-dose ethephon group [(0.63±0.11)%],there exists statistically significant difference(P<0.05).The spermatogenic cell AI in the medium-dose ethephon group is lower than that in the high-dose ethephon group,there exists a great statistically significant difference(P<0.01).At the age of 14 days,the spermatogenic cells AI in each group are(0.54±0.08)%,(0.65±0.11)%,(0.77±0.11)%,(0.88±0.10)%,the spermatogenic cells AI in all groups increased gradually.,there exists statistically difference(all P values<0.01).4 When the offspring rats are 7 days old and 14 days old,the sex hormone levels of each experimental group were lower than those of the control group.At the age of 7 days,the LH,FSH,E2 and T of the experimental group were decreased compared with the control group,and the difference was statistically significant(all P values<0.01).The LH and FSH of each experimental group were lower than that of the experimental group at 14 days old,and the difference was statistically significant(P<0.01).There was no significant difference between the low-dose ethephon group T and E2 compared with the control group(P>0.05).The medium-dose ethephon group and the high-dose ethephon group T and E2 were higher than the control group and the low-dose ethephon group.The difference was statistically significant(P<0.01).In the same experimental group,the LH,FSH,T and E2 of the 14 days old offspring male rats increased compared with the 7 days old offspring male rats,and the difference was statistically significant(P<0.01).ConclusionEthephon can retards testicles growth,cause a disorder of germ cell arrangement,increase the apoptosis of spermatogenic cells and decrease the levels of sex hormones in offspring male rats.These changes worsen as the dose of ethephon increases. |
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