1394: Relationship between Mast cell and Inos Expression in Testicular Tissue Associated with Infertility

INTRODUCTION AND OBJECTIVE: Pigment epithelium-derived factor (PEDF) is a secreted glycoprotein with potent anti-angiogenic and neurotrophic activities in many cell types.It has been implicated in the control of epithelial cell mass in the pancreas and prostate through its regulatory action on the adjacent vasculature.We postulated that PEDF may have a similar function in the testes, and ablation of PEDF in a murine model would result in heightened angiogenesis and epithelial hyperplasia.METHODS: PEDF-deficient mice were generated by homologous recombination in 129Sv ES cells using standard methods to replace exons 3 to 6 of the Serpinfl with a cassette containing an internal ribosomal entry site and the J3-galactosidase and neomycin-resistance genes.ES cells were injected into C57BI6 blastocysts.Resulting chimeras were mated to C57BI6 females.Mice heterozygous for the PEDF null allele were mated, and resulting mice homozygous for the null allele and littermates homozygous for the wild type PEDF allele were analyzed.Histologic evaluation of testicular tissue harvested from PEDF null animals aged 5-9 months (n=6) and age-matched wild type controls (n = 5) was performed.Formalin-fixed histologic sections were imrnunostained with anti-CD31 antibody and HPS for endothelial cells and fibrous tissue, respectively.Microvascular density was determined by counting CD31 positive vessels in five non-overlapping high power fields.RESULTS: There was no difference in the size and gross morphology of the testes in the two groups.Histologic examination of all of the PEDF null testes revealed a more than two fold increase in microvascular density with medial hyperplasia of the arterioles and multifocal Leydig cell hyperplasia.Developing germ cell morphological changes were seen with an increased nuclear to cytoplasmic ratio.Numerous, prominent, clear vacuoles were present within elongating spermatids and residual bodies.Microscopically, there was no apparent difference in sperm number per tubule between the PEDF null and wild type animals.CONCLUSIONS: These observations suggest that the anti-angiogenic action of PEDF on the testicular vasculature may be important as a negative regulator of epithelial cell growth and may impact on germ cell development.