-Female pregnant Sprague-Dawley rats were intragastrically (ig) administered di(n-butyl) phthalate (DBP) at four doses (0, 10, 50 and 100 mg/kg) during gestation days (GD) 12-21 (n = 5 per group). The age-related morphological changes of Leydig cell mitochondrion (LC-Mt) and testosterone biosynthesis enzymes/associated genes/proteins expression levels were investigated. As compared to the control (no DBP), the 10 mg, and 50 mg DBP dose groups, the 100 mg DBP dose group at weeks 5 and 7 showed a significant amount of small LC-Mt. Thereafter, from weeks 9 to 17, the LC-Mt size and quantity in the100 mg DBP dose group increased and became statistically similar to the other dose groups; hence, dose and time-dependent LC-Mt changes were observed. Throughout the study, the 100 mg DBP dose group had significantly lower testosterone levels. In addition, the 100 mg DBP dose group displayed lower StAR (StAR, steroidogenic acute regulatory protein) and P450scc (CYP11a1, cholesterol side-chain cleavage enzyme) levels at weeks 5 and 7, but they became statistically similar to all other dose groups at weeks 9 to 17; in contrast, the SR-B1 (Sarb1, scavenger receptor class B member 1) levels were similar for all DBP dose groups. The rats in utero 100 mg DBP /kg/day (GD 12-21) exposure results from this study indicate a dose-dependent, age-related morphological change in LC-Mt which are linked to reductions in testosterone biosynthesis genes / proteins expression, specifically StAR and P450scc.

Pregnant Sprague-Dawley rats were orally administered di( n-butyl)phthalate (DBP; 100 mg/kg/day) on gestation days (GD) 12 to 21. We investigated the male offspring and probed morphological alterations in Sertoli cells at 7, 9, 14, and 17 weeks of age. Parameters assessed in this study included offspring number, sex ratios, body weights, testis weights, seminiferous tubule (ST) profile numbers and diameters, number of vimentin-labeled Sertoli cells, and both testosterone and follicle-stimulating hormone (FSH) levels. Testicular weight/body weight ratios and the numbers and diameters of ST in maximum transverse testicular sections were statistically similar at weeks 7 and 9; however, at weeks 14 and 17, they were statistically different and displayed higher BrdU-positive Sertoli cells/Sertoli cell ratios in the DBP treatment group. Noteworthily, the serum FSH levels were higher and testicular testosterone levels were lower in the DBP treatment group. To our knowledge, the present study is the first to report that in utero DBP exposure significantly increased Sertoli cell numbers and their cellular proliferation from postpuberty to adulthood, with a significant decrease in testicular testosterone and an increase in FSH.

-The intermediate filament of mature Sertoli cells is vimentin (Vim).One of the toxicological consequences of phthalate exposure is a selective decrease in Vim, an intermediate-sized (10 nm) cytoplasmic microfilament, in Sertoli cells. Vim in Sertoli cells of rats exposed in utero to 100 mg/kg/ day di(n-butyl) phthalate (DBP) on gestation days 12-21 was quantified. Immunohistochemical analysis revealed that Vim aggregated in Sertoli cells, but desmin filaments did not. Vim images were extracted from electron microscopic images using the computer program Imaris (Bitplane Scientific, Zeiss) and analyzed using Image-Pro plus (Media Cybernetics, USA). The amount of perinuclear Vim located within 0.5 μm of the nuclear membrane, where most Vim is aggregated, and the Vim volume ratios of the DBP group were similar to those of the vehicle group at 7 and 9 weeks, but those of the DBP group had decreased 0.63-times at 14 weeks and 0.48-times at 17 weeks compared to those of the vehicle groups. The present study showed that the testicular toxicity of in utero exposure to DBP seemed to be delayed type toxicity, and showed that improved morphometric methods cold be used widely for quantitative analysis of cellular cytoplasmic filaments.

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I have retracted the above paper as Editor-in-Chief of The Journal of Toxicological Sciences since I have serious concerns about it, primarily due to inappropriate authorship on a non-negligible scale.When it was brought to my attention that there was inappropriate authorship in this paper, I contacted the co-authors to confirm this point. I found out that the majority of them considered their listing as co-authors to be inappropriate.In addition, the majority agreed to the retraction of this paper.These facts raise concerns about the paper. From the standpoint of maintaining the integrity of the research community, I felt that such a paper should be retracted at once.