Prenatal DEHP Exposure Induces Premature Testicular Aging by Promoting Leydig Cell Senescence through the MAPK Signaling Pathways

Abstract

Previous studies show that prenatal di‐(2‐ethylhexyl) phthalate (DEHP) exposure induces premature testicular aging. However, the evidence is weak, and the underlying mechanisms remain unclear. p38/extracellular signal‐regulated kinase (ERK)/c‐Jun NH(2)‐terminal kinase (JNK) MAPK pathways participate in aging. Leydig cell (LC) senescence results in testicular aging. Whether prenatal DEHP exposure induces premature testicular aging by promoting LC senescence warrants further study. Here, male mice undergo prenatal exposure to 500 mg per kg per day DEHP, and TM3 LCs are treated with 200 µm mono (2‐ethylhexyl) phthalate (MEHP). MAPK pathways, testicular toxicity, and senescent phenotypes (β‐gal activity, p21, p16, and cell cycle) of male mice and LCs are explored. Prenatal DEHP exposure induces premature testicular aging in middle‐aged mice (poor genital development, reduced testosterone synthesis, poor semen quality, increased β‐gal activity, and upregulated expression of p21 and p16). MEHP induces LCs senescence (cell cycle arrest, increased β‐gal activity, and upregulated expression of p21). p38 and JNK pathways are activated, and the ERK pathway is inactivated. In conclusion, prenatal DEHP exposure induces premature testicular aging by promoting LC senescence through MAPK signaling pathways.

Prenatal DEHP exposure induces lifelong testicular toxicity by continuously interfering with steroidogenic gene expression

“…The protein expression of LHCGR and HSD3B2 was down-regulated after DEHP exposure ( Figure 2L-2O ). Partial results were similar to our previous study ( 29 ). Therefore, DEHP induced immediate testicular injury in the neonatal stage by interfering with steroidogenic gene expression.…”

“…These results were verified by WB analysis ( Figure 3L-3N ). Partial results were similar to our previous study ( 29 ). These results indicated that prenatal DEHP exposure induced DSD and adult male disorders by interfering with steroidogenic gene expression.…”

“…Furthermore, the seminiferous tubules in the 1,000 mg/kg group were somewhat atrophic with thin and vacant tubes ( Figure 4L ). Partial results were similar to our previous study ( 29 ). These results indicated that prenatal DEHP exposure induced reproductive aging.…”

“…WB analysis showed that the MEHP downregulated the expressions of LHCGR, HSD3B2, and HSD17B3 ( Figure 5H-5K ). Partial results were similar to our previous study ( 29 ). In conclusion, MEHP inhibited testosterone synthesis by interfering with steroidogenic gene expression.…”

“…Through microscopic examination, we found that 200 µmol/L MEHP exposure rarely induced apoptosis of TM3 cells, but 400 µmol/L MEHP exposure induced apoptosis. According to previous studies ( 30 , 31 ) and our findings ( 29 ), 200 µmol/L MEHP was determined as the experimental group. Our cell experiments showed that MEHP inhibited the testosterone synthesis of LCs ( Figure 5A ).…”