Evaluation of Effects of Topical Estradiol Benzoate Application on Cutaneous Wound Healing in Ovariectomized Female Mice

Abstract

Estrogen promotes cutaneous wound healing in ovariectomized (OVX) female mice. However, the effects of topical estrogen application on wounds remain unclear. Therefore, the aim of this study was to compare the effects of topical estrogen application on wounds with standard treatment methods. Eight-week-old C57BL/6J female mice underwent OVX and received two full-thickness wounds four weeks later. Mice were divided into three groups: topical estradiol benzoate (EB) (0.75 μg/g/day) wound treatment, subcutaneous estradiol (E2) pellets (0.05 mg, 21 days), and topical E2 (0.01 g/day) skin application. Wound healing was observed until day 14. Wound area ratios were significantly smaller in the topical EB wound treatment group than in the subcutaneous E2 pellet group on days 1–14 (p < 0.05) and topical E2 skin application group on days 1–9 (p < 0.05). Neutrophil and macrophage numbers were significantly smaller in the topical EB wound treatment group than in the subcutaneous E2 pellet and topical E2 skin application groups on day 7 (p < 0.05). Moreover, the number of new blood vessels and ratio of myofibroblasts were significantly larger in the topical EB wound treatment group than in the subcutaneous E2 pellet and topical E2 application skin groups on day 7 (p < 0.05). These results demonstrate that the application of estrogen to wounds reduced inflammatory responses and promoted angiogenesis and wound contraction more than the two other standard treatment methods.

Estrogen Effects on Wound Healing

“…The ovary is the main source of estrogen in the premenopausal period, and granulosa cells are the key cells to produce estrogen [ 36 , 37 , 38 , 39 , 40 ]. Estrogen is also synthesized in skin tissue [ 41 ], presenting a concept termed “intracrinology” [ 42 ]. Crucially, estrogen regulation depends on estrogen-metabolism enzymes, which include aromatase, catalyzing the conversion of androgens (including dehydroepiandrosterone (DHEA) and testosterone) to estrogens, as well as 17β-hydroxysteroid dehydrogenase 1 and 17β-hydroxysteroid dehydrogenase 2 converting estrone to estradiol [ 42 ].…”

“…The action of these estrogen-like compounds on cells or tissues is far more complicated, although the main pathway might follow the classical ligand-mediated nuclear receptor signaling, such as estrogen receptors α and β (ERα and ERβ) located within the nuclei of target cells [ 46 , 47 ]. The absence of a ligand (estrogen) shows that ERs are associated with an inhibitory heat shock protein [ 41 ].…”

Non‐invasive longitudinal monitoring of angiogenesis in a murine full‐thickness cutaneous wound healing model using high‐resolution three‐dimensional ultrasound imaging

“…A CD31 antibody has frequently been used to stain endothelial cells. 11,21,24,25 In this study, the results of paired measurements obtained from 2D ultrasound images with the Color Doppler mode and immunohistologically stained sections on day 14 after wounding showed that Pearson's correlation coefficients were r=0.927, 0.871, 0.717, and 0.913 for wounds 1, 2, 3, and 4, respectively, indicating a correlation. This result showed that a strong correlation for % vascularity was obtained between paired 2D ultrasound imaging with the Color Doppler mode and sections immunohistologically stained for the anti-CD31 antibody.…”

“…However, the current result showed that half of the wounds were not completely covered with a new epithelium on day 14 after wounding, although the wounds generally heal with scars until day 14 after wounding. [19][20][21] Therefore, a longitudinally evaluating the distribution of vascular growth over the course of healing is a valuable approach, it is necessary to confirm this limitation near the future. In summary, our results indicate that high-resolution 3D ultrasound imaging is useful for longitudinally evaluating the distribution of vascular growth over the course of healing.…”

“…The wound area is shown as a ratio of the wound area every day to the initial wound area on day 0 when the wound was made, as described in our previous studies. [19][20][21] pre-examination: Image depth=6 mm, Doppler gain=30, Velocity=1, Wall filter=med, and persist=max. To acquire 3D images, 2D images with the B mode or Color Doppler mode were parallel and uniformly spaced at 100μm intervals over the length of the whole wound surface on days 9, 11, and 14 after wounding.…”