Figure 2.

Topography of immunoreactive surfactant protein A (SP-A) in the vaginal epithelium of nine postmenopausal women. Immunocytochemistry was carried out, as described in the Materials and methods, using Vector Red as the chromogenic substrate for the alkaline phosphatase reporter and haematoxylin to stain nuclei. (a) Panels 1–8: tissue sections from from four donors; panels 1, 3, 5 and 7 (upper panels) at lower magnification and panels 2, 4, 6 and 8 at higher magnification illustrate the large differences in thickness of vaginal epithelium of women not receiving oestrogen. Panels (a)7 and (a)8, as well as (f), show thickening of the epithelium (acanthosis) and keratinization of the superficial layer, a response to chronic trauma resulting from prolapse of the vagina. The most obvious structural difference between pre- and postmenopausal vagina is in the intermediate layer. It is much thinner and constitutes a much less distinct layer in the postmenopausal that in the oestrogenized premenopausal vaginal epithelium. Nevertheless, SP-A-immunopositive cells, although more patchy than in premenopausal vaginal mucosa, can be seen in the deep intermediate layer in all specimens and there are areas showing strong immunostaining for SP-A in the superficial layer. (b) Panels 1 and 2 show the more oestrogenized appearance of vaginal epithelium of one of the subjects prescribed equine oestrogens. It shows a better developed intermediate layer than in sections from the other 11 postmenopausal subjects and therefore a much clearer separation of the immunopositive cells in the deep intermediate layer and the immunopositive superficial layer. Panels (c)–(f) exemplify the marked variation in SP-A distribution in postmenopausal subjects.