Multiparity Causes Uncoordinated Activity of Pelvic- and Perineal-Striated Muscles and Urodynamic Changes in Rabbits

Abstract

Temporal and coordinated activation of pelvic- (pubococcygeous) and perineal- (bulbospongiosus and ischiocavernosus) striated muscles occurs during micturition in female rabbits. We have hypothesized that the coordinated activation of pelvic and perineal muscles is modified during the micturition of young multiparous rabbits. Young virgin and multiparous female chinchilla rabbits were used to simultaneously record cystometrograms and electromyograms of the pubococcygeous, ischocavernosus, and bulbospongiosus muscles. Bladder function was assessed using standard urodynamic variables. The temporal coordination of pelvic- and perineal-striated muscle activity was changed in multiparous rabbits. The cystometrogram recordings were different than those obtained from virgin rabbits, as seen in alterations of the threshold volume, the residual volume, the voiding duration, and the maximum pressure. In rabbits, we find that multiparity causes uncoordinated activity of pubococcygeous, ischiocavernosus, and bulbospongiosus muscles and modifies the urodynamics.

Role of Puborectalis Muscle in the Genesis of Urethral Pressure

“…16 In addition, similar to humans, a temporal coordination between the pelvic and perineal muscles during micturition and parity associated modification of functional properties of these muscles was also reported in the rabbit. 17 Our pharmacological studies confirm previous observations that UP is under the influence of smooth as well as striated muscles. 14,18,19 To our knowledge the novel aspect of our study is that not 1 but 2 skeletal muscle components, ie the RHB and PRM, contribute to urethral pressure.…”

Fiber type composition of pubococcygeus and bulbospongiosus striated muscles is modified by multiparity in the rabbit

“…Apart from the rat, the most used species to attain basic knowledge regarding the structure‐function relationship of pelvic floor muscles, the female rabbit is an alternative model organism since their muscles are well‐developed and accessible for morphometric and functional analyses. Previous studies in this model have reported that multiparity alters the reflex activity of the Pc and Bs muscles during the induced micturition . Besides plausible neurological alterations, it is clear that multiparity affects the morphometry of these muscles and reduces their contractile force .…”

“…Pelvic and perineal skeletal muscles play important roles in reproductive and excretory functions . Women are more prone than men to suffer pelvic floor dysfunctions, which is clearly linked to factors such as age, menopause, and the number of childbirths, among others .…”

The Role of Pelvic and Perineal Muscles in Reproductive and Excretory Functions

“…Multiparity (4 consecutive vaginal deliveries) causes uncoordinated activity of pelvic and perineal muscles, and modifies urodynamics ( Fig. 7; Martínez-Gómez et al, 2011). All multiparous rabbits included in that study had a pattern of muscle activity different than that of the virgin rabbits.…”

“…al., 2008). Also, both women and female rabbits have been reported that during childbirth damage is produced of the pelvic floor muscles and nerves, leading to cause uncoordinated activity of pelvic and perineal muscles, modifying the micturition and producing postpartum urinary incontinence (Deindl et al, 1998;Haylen, 2009;Martínez-Gómez et al, 2011).…”