Association between pelvic organ prolapse and stress urinary incontinence with collagen

Abstract

The aim of the present study was to investigate the ultrastructure and content of collagen in uterosacral ligaments and paraurethral tissues in patients with pelvic organ prolapse (POP) and stress urinary incontinence (SUI), analyzing the association between POP and collagen dysfunction. The study comprised three groups: Control, POP and POP with SUI (n=30 per group). Histological characteristics of collagen fiber were observed and the diameters were measured using light and electron microscopy to determine the Type I and Type III collagen content of the main ligament in the urethral specimens. In the POP and POP with SUI groups, observations included diffuse atrophy of smooth muscles, active fibroblast metabolism, swollen mitochondria and visible Golgi apparatus. The collagen fibril diameters in the cardinal ligaments, uterosacral ligaments and paraurethral tissues were significantly greater in the POP and POP with SUI groups compared with those in the control group (P<0.01). In addition, the expression levels of Type I and Type III collagen were significantly lower in the POP and POP with SUI groups when compared with the control group (P<0.01). In the POP with SUI group, pelvic tissues were frail, resulting in smooth muscle bundles comminuting and arranging in a disorganized pattern. Fibroblast and myoblast metabolisms were active and new microvascular cells were weak. However, the collagen fibril diameter increased. Thus, collagen and ultrastructural changes in the pelvic floor may be associated with the development of POP and SUI.

Keywords: collagen; pelvic organ prolapse; stress urinary incontinence; ultrastructure.

Figure 1

Light microscope observations of collagen and muscle fiber in the (A) POP and POP with SUI and (B) control groups (magnification, ×200). POP, pelvic organ prolapse; SUI, stress urinary incontinence.

Figure 2

Electron microscope observations of mitochondria in the (A) POP and POP with SUI and (B) control groups. (C) Fibroblast in the POP and POP with SUI groups and (D) muscle fibroblast in POP and POP with SUI group (bar, 5 nm). POP, pelvic organ prolapse; SUI, stress urinary incontinence.

Figure 3

Expression of Type I collagen in the (A) POP and POP with SUI and (B) control groups. Expression of Type III collagen in the (C) POP and POP with SUI and (D) control groups (magnification, ×200). POP, pelvic organ prolapse; SUI, stress urinary incontinence.