Morphometry of paravaginal ganglia from the pelvic plexus: impact of multiparity, primiparity, and pregnancy

Abstract

Objectives: (1) To describe the morphology of paravaginal ganglia and the neurochemical pattern of their neurons in virgin rabbits. (2) To analyze the effects of multiparity, primiparity and late pregnancy on morphometry of ganglia and their neurons.

Study design: The morphology and neurochemical pattern of paravaginal ganglia were described in virgin nulliparous Chinchilla breed rabbits. Acetylcholinesterase histochemistry, Masson's trichrome, and immunohistochemistry for cholinergic and adrenergic neurons, and estrogen receptors (ERs) were undertaken. The area covered by ganglia (ganglionic area), the number of neurons, and the neuron soma area were measured in multiparas (4 consecutive and successive deliveries) and age-matched nulliparas. The same variables were measured in primiparous, late-pregnant, and age-matched nulliparous rabbits.

Results: Paravaginal ganglia were adjoined to the dorsolateral walls of the pelvic vagina. Their neurons were mostly cholinergic and expressed ERα and ERβ. Multiparity increased the ganglionic area and reduced the number of ganglionic neurons. Late pregnancy transiently reduced the neuron soma area, which was coincident with a low expression of ERs.

Conclusion: Multiparity but not primiparity affected the morphometry of ganglia. The hormonal state present in late pregnancy alters the neuron soma area and ER expression. Our findings support the notion that reproduction influences the morphometry of the pelvic plexus.

Keywords: Choline acetyltransferase; Estrogen receptor; Inferior hypogastric plexus; Lower urogenital tract; Pelvic ganglia; Rabbit; Tyrosine hydroxylase.