The OVX and OVX + EA groups underwent bilateral ovariectomy after isoflurane anesthesia. Bilateral ovaries were ligated and dissected following the protocol of Souza et al.[35] . The control group underwent sham surgery, and only a small amount of fat tissue around the ovaries was dissected out. After surgery, daily intramuscular injection of penicillin (2,500 U) was administered for 3 days. Two weeks after ovariectomy, mice in the OVX + EA group received 3 days of EA treatment. Estrogen was assayed with enzyme-linked immunosorbent assay (ELISA) kit (Beijing Sino-UK Institute of Biological Technology) following the manufacturer’s protocol.
For uterine histology and morphometry, each uterus was dissected completely from the junction of the cervix, and uterine weight was recorded after removing the peripheral fat and excess fluid. The uterus was then kept in 4% PFA at room temperature for 24 h, embedded in paraffin, and sectioned at a thickness of 5 μm followed by hematoxylin and eosin staining (Thermo Fisher Scientific, USA).
For uterine histology and morphometry, each uterus was dissected completely from the junction of the cervix, and uterine weight was recorded after removing the peripheral fat and excess fluid. The uterus was then kept in 4% PFA at room temperature for 24 h, embedded in paraffin, and sectioned at a thickness of 5 μm followed by hematoxylin and eosin staining (Thermo Fisher Scientific, USA).