Effects of ovariectomy-induced estrogen deficit on rat behaviour, lipid metabolism, inflammation, bone mineral density, and turnover.

Aim: The objective of the present study was to make a complex evaluation of behaviour, lipid metabolism, inflammation, and bone turnover in an ovariectomized rat model used to simulate postmenopausal clinical findings.
Materials and Methods: Female Wistar rats were divided into 2 groups of 16 animals each: sham operated (SO) animals and ovariectomized (OVX) animals. Three months after the operation, a battery of behavioural tests was performed including an open field test (OFT), elevated pus-maze test (EPM), the social interaction test (SIT), the forced swim test (FST), and a hot plate test (HPT). At termination of experiment, weight gain and fat deposits (total and retroperitoneal) were measured. Serum concentrations of blood lipids were determined. Tumor necrosis factor alpha (TNF-alpha) and alkaline phosphatase (ALP) serum concentrations were used for evaluation of the inflammation and bone turnover, respectively. Femur bone mineral density (BMD) was evaluated using dual energy X-ray absorptiometry.
Results: OVX rats did not demonstrate any significant behavioural changes in OFT and EPM tests but showed a decreased interaction time in SIT and an increased immobility time in FST test which indicated anxiety and depression. The OVX rats had a significantly lower pain sensitivity threshold. They had greater weight gain, increased total and retroperitoneal fat deposits, as well as elevated total fat/body weight and retroperitoneal fat/body weight ratios. Blood cholesterol, ALP and TNF-alpha of the OVX group were also significantly higher. Femur BMD of OVX rats was slightly but not significantly reduced.
Conclusions: Estrogen deficiency in OVX rats caused depression, anxiety, hyperalgesia, obesity, dyslipidemia, and inflammation before the reduction in bone mineral density was prominent.
(This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.)