Citrate synthase, sarcoplasmic reticular calcium ATPase, and choline acetyltransferase activities of specific pelvic floor muscles of the rabbit

Abstract

There is a clear relationship between the pelvic floor muscles and urinary systems, which relates to urgency, frequency, incontinence, pelvic pain, and bowel complaints. The specific mechanisms which relate these two systems are not clear. Improved understanding of the relation between the pelvic floor muscles and bladder function is clinically relevant in establishing effective treatments to such problems as incontinence, secondary to birth. The following tissues were collected from normal adult female rabbits: pubococcygeus (Pc) and ischiocavernosus/bulbospongiosus (Ic/Bs) pelvic floor muscles. Bladder body muscle and mucosa, bladder base muscle and mucosa, and leg skeletal muscle were also collected. The following enzymatic assays were performed on each tissue: citrate synthase (CS), sarcoplasmic-endoplasmic reticular ATPase (SERCA), and choline acetyltransferase (ChAT). CS and SERCA activities were significantly higher in the Pc compared with the Ic/Bs pelvic floor muscles, whereas the ChAT activity of the Ic/Bs was higher than that of the Pc muscle. Based on our results, the Pc muscle is expected to have a significantly greater capacity to contract and a higher metabolic activity than those of the Ic/Bs muscles. We believe that an understanding of the biochemical activities of these three biomarker enzymes in normal pelvic floor muscles is essential in evaluating the effects of specific experimental dysfunctions created in pelvic floor muscle activity.

Differential damage and repair responses of pubococcygeus and bulbospongiosus muscles in multiparous rabbits

“…Importantly, the estrogenic state influences cellular events in terms of both muscle damage (e.g., inflammation) and muscle regeneration (e.g., activation of SC) . Apart from the anatomical location of the Pcm and Bsm, biochemical characteristics including the myofiber composition of both muscles could also influence the extent of the multiparity‐induced injury, and, thereafter, the particular muscle regeneration.…”

“…These muscles are differently affected by multiparity as shown by morphometric and functional analyses . Some of these effects could be related to anatomical and biochemical differences between the Pcm and Bsm, albeit the influence of muscle damage and and/or recovery can not be discarded. Indeed, some morphologic alterations observed in the Pcm, but not in the Bsm, have been suggested as transient histomorphologic signs of muscle damage …”

Hypothyroidism modifies morphometry and thyroid‐hormone receptor expression in periurethral muscles of female rabbits

“…Twelve 9–13 months old European chinchilla‐breed virgin female rabbits ( Oryctolagus cuniculus ) weighing 3.8–4.7 kg were allocated into control (CTL, n = 6) and hypothyroid (HT, n = 6) groups. The sample size (n = 6) was chosen considering other studies where female rabbits were used as experimental subjects to evaluate physiological and/or morphometrical properties of pelvic and perineal skeletal muscles . The rabbits were housed in individual stainless‐steel cages and kept at 20 ± 2°C room temperature under artificial lighting conditions (16:8 h light: dark; lights on at 06:00).…”

“…Female rabbits have conspicuous pelvic and perineal skeletal muscles that make them suitable for evaluating function and morphometry . Studies done in female rabbits have showed noticeable differences in metabolism and fiber type content between the pubococcygeus (Pcm), a pelvic muscle, and the bulbospongiosus (Bsm), a perineal muscle . The former is composed of a heterogeneous proportion of slow‐oxidative (type 1a), fast oxidative‐glycolytic (type IIa/d), and fast glycolytic fibers (type IIb), while the latter is predominantly composed of fast glycolytic fibers.…”