Abstract. In order to study the effects of vertically transferred coplanar polychlorinated biphenyls on female reproductive development, female rat offspring from dams of Sprague-Dawley strain, which received daily oral administration of vehicle (corn oil) or 1 or 3 µg/kg of 3,3',4,4',5-pentachlorobiphenyl (PCB-126) from 2 weeks prior to mating with intact males until 20 days after delivery were examined from birth until puberty. Hepatic expression of the aryl hydrocarbon receptor (AhR)-inducible enzyme cytochrome P450 1A1 (CYP1A1) was detected in all offspring from PCB-126-exposed dams, indicating vertical transfer of PCB-126. Furthermore, quantification of ovarian mRNAs encoding CYP1A1, AhR and ARNT demonstrated that the ovary equipped the AhRsignaling system through which transcription of the CYP1A1 gene was enhanced in a dose-dependent manner. Exposure to PCB-126 retarded the growth of offspring in both exposed groups, while the viability of the neonates of the exposed groups was comparable to that of the oil-exposed controls.The exposure to 3 µg/kg/day reduced the ovarian weight on postnatal day (PND) 24, with atresia of most of the antral follicles and delayed vaginal opening. Exposure to 1 µg/kg/day did not produce such effects; however, both doses of PCB-126 induced external urogenital anomalies, such as vaginal thread and hypospadias, in all of the PCB-126-exposed female offspring. These results indicate that vertically transferred PCB-126 is potent enough to exert a direct effect on the ovary and adversely affect female puberty by altering the morphological and functional development of the female reproductive system.

ABSTRACT. Angiogenesis is essential for tumor progression and is regulated by several angiogenic factors such as vascular endothelial growth factor (VEGF). We investigated the expression and distribution of VEGF and its receptor flt-1 in twelve normal canine tissues in six beagle dogs using immunohistochemistry, RT-PCR and real-time RT-PCR. Immunochemical staining showed that both VEGF and flt-1 were expressed in many tissues and their mRNAs were detected in all organs examined by RT-PCR. Levels of VEGF164 and flt-1 mRNA expression were high in tissues containing many intensely immunopositive cells. The expression levels of VEGF164 and flt-1 mRNA tended to be similar. These results indicated that VEGF and flt-1 are closely associated in canine, as in human tissues, and quantifying their mRNAs might be helpful in evaluating angiogenesis. KEY WORDS: canine, flt-1, VEGF.

-Busulfan, an antineoplastic agent that targets small follicles (primordial and primary follicles), was given orally to female Sprague-Dawley rats (0, 0.1, 0.5, or 1.5 mg/kg/day; n = 10 in each ovarian morphology. Isolated ovaries were used for histopathological analysis and follicle counts. In addition, a female fertility study was conducted by giving the same dose levels of busulfan from 2 weeks female reproduction. In the 2-week study, all rats treated with busulfan showed normal estrous cyclicity number of small follicles at 1.5 mg/kg. In the female fertility study, increases in dead embryos and post--ductive performance and 0.5 mg/kg for early embryonic development. In conclusion, the present study -logical analysis of stage-based follicles are needed to detect small follicle depletion in a general toxicity

The recent development of the laser microdissection (LMD) technique enables one to target particular tissues or cells for gene or protein analyses. The purpose of this study was to detect local mRNA expression of vascular endothelial growth factor (VEGF) and its receptor, flk-1, in the glomeruli of normal rat kidneys using the LMD system. Frozen sections of the kidney of 8-week-old male Wistar rats were made. The glomeruli were dissected from the frozen sections with the LMD system, and total RNA was extracted from 200 glomeruli in each kidney. Reverse-transcription polymerase chain reaction (RT-PCR) revealed the local mRNA expression of three isoforms of VEGF, flk-1 and GAPDH in the glomeruli. Moreover, the real-time PCR was performed to evaluate the experimental condition for quantification of VEGF and flk-1 mRNA expression using this system, and the results showed that at least 10 glomeruli might be needed for quantifying local VEGF mRNA expression. However, cDNA from 200 glomeruli was not enough for quantitative evaluation of flk-1 mRNA with this system. These results demonstrate the reproducibility of the analysis of mRNA expression in the renal glomeruli using the LMD system and also suggest that the application of the LMD technique will provide information to further our understanding of the mechanisms involved in kidney diseases.

ABSTRACT. In order to understand ovarian toxicity of aryl hydrocarbon receptor (AhR) agonists, in situ gene expression of the AhR was examined during follicle development in immature rats. In situ hybridization on frozen sections of ovaries from 24-day-old SpragueDawley rats showed that the AhR mRNA was localized in the granulosa cells and occasionally in the theca cells of the follicles irrespective of the developmental stage. In situ gene quantification on granulosa cell layers collected by laser microdissection further revealed that the granulosa cells expressed less AhR mRNA according to development of belonging follicles, but more -subunit of inhibin A mRNA, a quality control gene. These results may help to elucidate vulnerable developmental stages of follicles to toxicities of the AhR agonists.KEY WORDS: aryl hydrocarbon receptor (AhR), -subunit of inhibin A, follicular development, laser microdissection, ovary.J. Vet. Med. Sci. 73(7): 923-926, 2011 Aryl hydrocarbon receptor (AhR) is a ligand-activated transcription factor that mediates toxicity of AhR agonists, such as the polycyclic aromatic hydrocarbons (PAHs) [2,6,12], and is expressed in mammalian ovaries [2]. Treatment with AhR agonists such as 2,3,7,8-tetrachlorodibenzo-pdioxin [16] and 3,3',4,4', [17] increases cytochrome P450 (CYP) 1A1 mRNA, a phase I enzyme, in rat ovaries, indicating that AhR signaling cascades are activated. Ligand-activated AhR regulates the ovarian atresia in primordial and primary follicles via activation of the Bax signaling pathway [9,10], and ovotoxicity induced by PAH is prevented by the concomitant treatment with AhR antagonists, thus indicating that AhR is the key mediator of ovotoxicity [11]. Although AhR has been confirmed in oocytes, granulosa and theca cells of growing follicles in the rat by its mRNA and protein expression levels [4,13], little has been studied precise expression level of the AhR in the follicles at each developmental stage. Therefore, the present study was designed to examine in situ expression of the AhR mRNA by in situ hybridization (ISH) and gene quantification of laser-dissected granulosa cell layers from healthy follicles at different developmental stages. The mRNA encoding the -subunit of inhibin A was also quantified to confirm the quality of the dissected specimens, since striking and dynamic changes of the -subunit of inhibin A mRNA have been detected in rats during developmental maturation of the follicles [18], and increased inhibin A secretion occurs with the advancing estrous cycle up to the LH surge [8].In this study, three females born in our animal facility from pregnant Sprague-Dawley rats (Charles River Japan, Yokohama, Japan) were used after weaning on postnatal day (PND) 21 in accordance with the guidelines approved by the Animal Research Committee of Azabu University. On PND 24, the rats were sacrificed by decapitation, and their ovaries were collected, frozen in liquid nitrogen and stored at -80C until analyses.For the ISH and the in situ gene quantification, frozen ...