Study of fallopian tube anatomy and mechanical properties to determine pressure limits for endoscopic exploration.

Falloposcopy is the endoscopic examination of the fallopian tubes, which are challenging to access due to their deep body location, small opening from the uterus, and lumen filled with plicae. We and others have developed endoscopes that are inserted through the uterus guided by a hysteroscope into the tubal ostium. To better understand how to utilize these endoscopes either as standalone devices or in concert with everting delivery balloons, a preliminary study of anatomy and mechanical behavior was performed ex vivo on porcine and human fallopian tubes. Segments of fallopian tubes from the isthmus, ampulla and infundibulum were inflated with saline either to bursting or held at sub-burst pressures with saline or a saline-filled balloon. Formalin fixed, paraffin embedded tissue sections stained with Masson's trichrome were examined for damage to the mucosa and muscularis. Porcine fallopian tubes tolerated saline pressurization at 15 psi for 1 minute without morphological damage. Balloon inflation to 15 psi caused no apparent damage to the muscle layer or rupture of the fallopian tube, but balloon movement within the tube can denude the mucosal epithelial layer. Human fallopian tubes averaged higher burst pressure values than porcine tubes. Under pressurization, the external tube diameter expanded by minimal to moderate amounts. Human and porcine tissues were similar in histological appearance. These studies suggest that moderate pressurization is acceptable but will not appreciably expand the fallopian tube diameter. The results also indicate that pigs are a reasonable model to study damage from falloscopy as seen in human tissue.

Comparison of Reproductive Function in Female TgMISIIR-TAg Transgenic and Wildtype C57BL/6 Mice.

Transgenic TgMISIIR-TAg (TAg) mice express the oncogenic virus SV40 in Mullerian epithelial cells. Female TAg mice spontaneously develop epithelial ovarian carcinoma, the most common type of ovarian cancer in women. Female TAg mice are infertile, but the reason has not been determined. We therefore investigated whether female TAg mice undergo puberty, demonstrate follicular development, maintain regular cycles, and ovulate. Ovarian cancers in women commonly develop after menopause. The occupational chemical 4-vinylcyclohexene diepoxide (VCD) accelerates follicle degeneration in the ovaries of rats and mice, causing early ovarian failure. We therefore used VCD dosing of mice to develop an animal model for menopause. The purpose of this study was to characterize reproductive parameters in female TAg mice and to investigate whether the onset of ovarian failure due VCD dosing differed between female TAg and WT C57BL/6 mice. As in WT female mice, TAg female mice underwent puberty (vaginal opening) and developed cyclicity in patterns that were similar between the groups. Vehicle-only TAg mice had fewer ovulations (numbers of corpora lutea) than WT animals. VCD exposure delayed the onset of puberty (day of first estrus) in TAg as compared with WT mice. Morphologic evaluation of ovaries revealed many more degenerating follicles in TAg mice than WT mice, and more VCD-dosed TAg mice were in ovarian failure than VCD-dosed WT mice. These results suggest that despite showing similar onset of sexual maturation, TAg mice have increased follicular degeneration and fewer ovulations than WT. These features may contribute to the inability of female TAg mice to reproduce.