Intrauterine adhesions (IUA) frequently occur after infectious or mechanical injury to the endometrium, which may lead to infertility and/or pregnancy complications. There are few effective treatments due to the complex function of endometrium and shortage of native materials. 17β-estradiol (E
2
) is commonly used as an ancillary treatment in IUA patients, but it is limited by its poor solubility in aqueous solutions and low concentrations at the injured sites. In this research, a mini-endometrial curette was used to injure the rat’s endometrium to form an IUA model. 17β-estradiol was encapsulated into the micelles of heparin-poloxamer and a thermosensitive hydrogel (E
2
-HP hydrogel) was formed. This sustained releasing system was applied to restore the structure and function of the injured uterus. E
2
-HP hydrogel was constructed and relevant characteristics including gelation temperature and micromorphology were evaluated. Sustained release of 17β-estradiol from HP hydrogel was performed both in vitro and in vivo. Ultrasonography measurement and pathologic characteristics on the IUA rats were performed to evaluate the therapeutic effect of E
2
-HP hydrogel. Endoplasmic reticulum (ER) stress-related apoptosis was analyzed to explore the possible mechanisms in IUA recovery. E
2
-HP hydrogel showed a prolonged release of E
2
at the targeting region and more effective endometrium regeneration in IUA rats. Significant improvements in both gland numbers and fibrosis area were observed in the E
2
-HP hydrogel group. We also demonstrated that E
2
-HP hydrogel in the recovery of IUA was closely related to the suppression of ER stress signals via the activation of downstream signals, PI3K/Akt and ERK1/2. HP hydrogel might be an effective approach to deliver E
2
into the injured endometrium. Therapeutic strategies targeting ER stress using E
2
-HP hydrogel might be a promising solution for the treatment of women with intrauterine adhesions.
Ca-alginate-poly-l-lysine-alginate (APA-Ca) and Ba-alginate-poly-l-lysine-alginate (APA-Ba) microcapsules were prepared and their thickness and surface were examined by light microscopy and scanning electron microscopy. Specifically, light microscopy with frozen section was used to visualize and quantify the thickness of APA membrane, and monitor temporal changes in the thickness of microcapsules during a month long culture in vitro. The section graph of APA microcapsule represents the accurate measurement of layer thickness of APA-Ca with diameter 900 ± 100 and 500 ± 100 μm at 6.01 ± 1.02 and 9.54 ± 2.42 μm (p < 0.05), and layer thickness of APA-Ba with diameter 900 ± 100 and 500 ± 100 μm at 5.47 ± 0.90 and 8.21 ± 1.97 μm (p < 0.05), regardless of the alginate composition used to generate the microcapsules. The microcapsule was stable during the culture for 30 days in vitro. Field emission scanning electron microscopy with freeze drying method was used to detect the surface and thickness of dried microcapsules. From the results, the outer surface of APA-Ca and APA-Ba membrane were smooth and dense, the film thickness of the APA-Ca was about 450-690 nm, while the APA-Ba was approximately 335 nm. In vivo experiment, little significant difference was seen in the change of film thickness of microcapsules in intrapertioneal site for 30 days after transplantation (p > 0.05), except that the recovery of APA-Ba was higher than the APA-Ca microcapsules. The paper showed an easy method to prepare APA-Ca and APA-Ba, and examine their thickness and surface, which could be utilized to study other types of microcapsules.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.