Tissue alterations in urethral and vaginal walls related to multiparity in rabbits

Abstract

In rodents, vaginal distention after delivery or experimental manipulation affects innervations as well as the amount of striated/smooth musculature or collagen in both the urethra and vagina. These changes are associated with modifications in excretory and reproductive processes. Although successive and consecutive vaginal deliveries (multiparity) affect the contractile and functional properties of the female lower urogenital tract (LUT), its impact on LUT morphometry, including persistency, has been barely studied. The caudal urethra (CU) and cranial (V1) and caudal (V2) pelvic vaginal regions were excised from young and adult nulliparous (YN and AN, respectively) and multiparous (YM and AM, respectively) rabbits. Tissues were histologically processed and stained with Masson's trichrome. The thickness of the tissue layers and areas covered by tissue components were measured and compared using two-way ANOVA followed by Student-Newmann-Keuls tests to determine statistical differences (P 0.05). Compared to YN, YM, and AN tissues showed a reduction in the thickness of the epithelium, as well as in areas covered by striated musculature, collagen, and blood vessels of the LUT. In comparison with YM, only some morphometric changes were recovered in the AM group. Our study shows that multiparity and age can be associated with epithelial and muscular atrophy of urethral and vaginal walls. The morphometry of the LUT between young and adult female rabbits varies with multiparity. These findings may help to better understand the effects of multiparity on young and adult females and its correlation with the development of pelvic dysfunctions. Anat Rec, 297:1963Rec, 297: -1970Rec, 297: , 2014

Developing a Simple Proof of Concept Clinical Decision-Making Tool for Predicting Surgical Outcomes after Obstetric Fistula Repair in a Developing Country

“…The association between parity and surgical outcomes seems biologically plausible. Grand multiparity has been shown to be associated with tissue alterations in urethral and vaginal walls in animal studies [39]. This may explain the decreased odds of success observed among grand multiparous women.…”

Is Mode of Delivery Associated With Sexual Response? A Pilot Study of Genital and Subjective Sexual Arousal in Primiparous Women With Vaginal or Cesarean Section Births

“…55 Indeed, traumatic injury to the internal pudendal arterial bed from blunt trauma or chronic perineal pressure can result in reduced genital blood flow. 58 Alternatively, animal models suggest that vaginal delivery can alter vaginal morphology, epithelium, and smooth muscle, 59,60 all of which play a role in female genital response. 61 What is the Clinical Significance of Low Genital Response?…”

Multiparity modifies contractile properties of pelvic muscles affecting the genesis of vaginal pressure in rabbits

“…In contrast, there was an increase in the contraction of the Pcm and the pressure of the pelvic vagina. If well, changes in the genesis of vaginal pressure could be linked to multiparity‐altered contractile properties of Bsm, Ism, and Pcm, the modifications in the histological organization of rabbit vagina should be also considered . This is particularly relevant for the connective tissue since transient modifications involving the types of collagen in multiparous rats have been reported .…”

“…Moreover, multiparity modifies the fiber type composition of Bsm and Pcm . In addition to striated muscle alterations, multiparity also impairs the histological organization of the vagina . Considering these findings, the anatomical relationship and reflex activity of Bsm, Ism, and Pcm with the vagina and during vaginal stimulation, we have hypothesized herein that multiparity alterates the contractility of these muscles affecting the genesis of the vaginal pressure.…”