This study was conducted to determine the functional role of phospholipase D (PLD) involved in testicular Leydig cell damage caused by di (2-ethylhexyl) phthalate (DEHP) in Sprague-Dawley rats. DEHP (500 mg/kg/day) was administered orally to prepubertal rats for 1, 7, 14, 21 or 28 days. After 7 days of exposure, DEHP produced morphological changes in the testis, including alterations in seminiferous tubule diameters and loss of spermatogenic cells. Immunohistochemistry (IHC) analyses revealed that DEHP increased Leydig cell number in the testes as well as significantly increased the expression of PLD1/2 in Leydig cells after 7 days of exposure. Furthermore, the protein levels of phosphorylated extracellular signal-regulated kinase 1/2 (pERK1/2) increased in a similar manner to the PLD1/2 expression patterns. DEHP significantly reduced the expression of sperm-associated antigen 4 (Spag4) and lactate dehydrogenase A (LDHA) mRNA. In contrast, there was a significant increase in the expression of steroidogenic acute regulatory (StAR) mRNA against DEHP in a time-dependent manner, but serum testosterone concentration was decreased. These findings demonstrate that DEHP induces PLD expression in the testicular Leydig cells; this plays a key role in hyperplasia of Leydig cells and steroidogenic pathway via pERK1/2 activation.
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Acknowledgments We thank Prof. Byung Mu Lee for discussion that inspired us to perform this study. We also thank Hae Young Chung and Jee H. Jung for helpful comments on the manuscript. Lee Y.J. and Ahn M.Y. were supported by grants from the Brain Korea 21 project. We thank Aging Tissue Bank for providing research resources.
All Science Journal Classification (ASJC) codes
- Health, Toxicology and Mutagenesis