Localization and quantity of hyaluronan in urogenital organs of male and female rats.

The histochemical distribution of hyaluronan was analysed in various urogenital organs of male and female (non-pregnant and pregnant) rats by use of a hyaluronan-binding protein and avidin biotin/peroxidase staining. Microwave-aided fixation was used to preserve the extracellular location of hyaluronan. The concentrations of hyaluronan in the different tissues were measured with a highly sensitive radio-assay. Hyaluronan accumulated predominantly in the connective tissue around smooth muscle fibres and in the subepithelial lamina propria. Abundant hyaluronan also occurred in perivascular and perineural connective tissue. In the female urogenital organs, hyaluronan content was high in the vagina and urinary bladder, and highest in the vagina during pregnancy. In the uterus, the surface epithelium of the endometrium stained intensely. In the ovary, the zona pellucida of the oocyte and the theca interna cell layer of the follicles and the follicular fluid of mature follicles exhibited prominent staining. The corpus luteum was devoid of hyaluronan, whereas enlarged corpora lutea of pregnancy exhibited weak, patchy staining. In male urogenital organs, staining for hyaluronan was absent from the testis and epididymis, whereas the erectile connective tissue of the penis stained intensely. The hyaluronan concentrations were high in penile tissue and urinary bladder, while testis, epididymis and the ductus deferens contained only little hyaluronan.