Résumé
Objective:To investigate the effect of ethephon exposure on sperm quality of adolescent male SD rats and the influence mechanism.Methods:A total of 40 45-day-old male SD rats were divided into control group and low, middle and high experimental groups according to the random number table method, 10 rats in each group.The said 4 groups were given 9 g/L normal saline, 100 mg/kg, 200 mg/kg, and 400 mg/kg ethephon aqueous solution for 28 days, respectively.One epididymal tail was taken to prepare sperm suspension, the sperm concentration and motility were detected.The testis and epididymis tissues were stained with HE, and their pathological changes were observed under light microscope.The activities of superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px), and the malondialdehyde (MDA) content in the testis were detected.Enzyme linked immunosorbent assay kit was used to mea-sure the epididymal α-glucosidase activity, L-carnitine (LC) content, nuclear factor erythroid 2-related factor 2 (Nrf2) and organic cation transporter 2 (OCTN2) expression levels.Then the oxidative damage caused by ethephon to epididymis was evaluated.SPSS 26.0 software was used for data analysis.Data were compared by One- way ANOVA among groups and LSD method between 2 groups. Results:The sperm concentration of the control group, low, medium and high dose groups were (40.21±1.94)×10 9/L, (35.23±2.53)×10 9/L, (23.61±2.62)×10 9 /L, and (18.86±2.16)×10 9 /L, respectively.The sperm activity rate were (70.98±3.01)%, (57.96±3.75)%, (45.71±2.41)%, and (31.23±2.26)%, respectively.The concentration and vitality of epididymal sperms in the experimental group were significantly lower than those in the control group (all P<0.01). In the control group, low, medium and high dose groups, the SOD activity were (46.48±2.21) U/mg prot, (38.49±2.56)U/mg prot, (33.80±1.73) U/mg prot, and (27.65±2.05) U/mg prot, respectively.The GSH-Px activity in said 4 groups were (21.41±1.95) U/mg prot, (17.32±1.28) U/mg prot, (15.09±0.94) U/mg prot, and (14.08±1.23) U/mg prot, respectively.The MDA content in said 4 groups were (1.41±0.09) nmol/mg prot, (1.59±0.09) nmol/mg prot, (1.81±0.09) nmol/mg prot, and (2.16±0.14) nmol/mg prot, respectively.Compared to the control group, the experimental groups had significantly lower SOD and GSH-Px activities and significantly higher MDA content (all P<0.05). α-glucosidase levels in the control group, low, middle and high experimental groups were (15.46±0.71) U/mL prot, (12.95±0.72) U/mL prot, (11.34±0.65) U/mL prot, and (8.76±0.60) U/mL prot, respectively.LC levels in the control group, low, middle and high dose groups were(6.21±0.31) μg/L, (5.89±0.13) μg/L, (5.02±0.12) μg/L, (4.38±0.07) μg/L, respectively, compared with those of the control group, the concentration of α-glucosidase and LC in experimental groups decreased significantly (all P<0.01). The expression levels of Nrf2 in epididymis of the control group, low, middle and high dose groups were (1.34±0.05) ng/L, (1.25±0.04) ng/L, (1.08±0.06) ng/L, (0.92±0.04) ng/L, respectively; the expression levels of OCTN2 in epididymis of the control group, low, middle and high dose groups were (4.55±0.12) ng/L, (4.23±0.11) ng/L, (3.20±0.24) ng/L, (2.59±0.05) ng/L, respectively, compared with those of the control group, the expression levels of Nrf2 and OCTN2 in experimental groups decreased significantly (all P<0.01). Conclusions:Ethephon exposure leads to excessive generation of reactive oxygen and oxidative stress in reproductive organs.Ethephon exposure may activate the Keap1-Nrf2/ARE signal pathway, resulting in a decrease in the number, vitality and quality of sperms, and impaired fertility.
Résumé
Objective:To explore the effects of different doses of Ethephon on testes of male pups.Methods:Thirty-two 45-day-old healthy female Sprague-Dawley (SD) rats were randomly divided into the control group and the low dose, middle dose and high dose Ethephon groups by the random figure table.The female rats in the low dose, middle dose and high dose Ethephon groups were given 200, 400, and 800 mg/kg Ethephon solution, respectively.The control group was treated with 9 g/L saline.After the birth of the offspring, the mother rats were not administrated with any medications, and the male offspring rats were given Ethephon solution instead.Twelve offspring male rats were randomly selected from each group and killed at the age of 0, 14 and 28 days after birth.Fresh testicular tissues were stained with hematoxylin eosin (HE), and the morphological changes of testicular tissues were observed under light microscope.The apoptotic cells were labeled by terminal dexynucleotidyl transferase (TdT) mediated dUTP nick end labeling (TUNEL) method and the apoptosis index (AI) of spermatogenic cells was detected by fluorescence microscope.Results:(1) Compared with the newborn rats in the middle dose group, low dose group and control group, se-miniferous tubules in the newborn rats of the high dose group were slightly thicker, and seminiferous cells were arranged slightly in disorder.The AI of the newborn rats in high dose group was significantly higher than that in the control group (1.00±0.06 vs.0.41±0.03, P<0.01). The AI of the newborn rats in the middle dose group was not significantly different from that in the control group and the low dose group ( P>0.05). (2) The seminiferous tubules of the 14-day-old rats in the low dose, middle dose and high dose Ethephon groups were significantly thicker and arranged more loosely than those in the control group.Compared with the control group, there were very few seminiferous cells, which were arranged disorderly in the low dose, middle dose and high dose Ethephon groups.The AI of the 14-day-old rats in the low dose, middle dose and high dose Ethephon groups was (2.13±0.10), (2.18±0.10) and (3.90±0.23), respectively, which were significantly higher than that in the control group (1.00±0.02) ( F=2 508.36, P<0.01). There was no significant difference in the AI between the middle dose and low dose groups ( P>0.05). (3) Compared with the control group, the seminiferous tubules of the 28-day-old rats in the low dose, middle dose and high dose groups were significantly thicker and arranged much more loosely, and spermatogenic cells were even less and arranged in a severely disordered way.The AI of 28-day-old rats in the low dose group (5.52±0.13), the middle dose group (9.44±0.07) and the high dose group (14.56±0.27) was significantly higher than that in the control group (3.11±0.13) ( F=10 784.69, P<0.01). Conclusions:Ethephon can thicken the seminiferous tubules of newborn and young rats, cause the germ cells to arrange disorderly, promote the apoptosis of spermatogenic cells and reduce the ability of spermatogenesis.Moreover, a longer exposure of the rats to a higher concentration of Ethephon will result in more serious damage to testicular tissues.