Effects of estrogen via estrogen receptors on parvalbumin levels in cardiac myocytes of ovariectomized rats

作者：Wirakiat Wimon; Udomuksorn Wandee; Vongvatcharanon Surapong; Vongvatcharanon Ura****^*

来源：Acta Histochemica, 2012, 114(1): 46-54.

DOI：10.1016/j.acthis.2011.02.004

• Estrogen
• Estrogen receptor
• Parvalbumin
• Ovariectomy
• Cardiac myocyte
• Calcium-binding protein
• Rat

The study investigated the effects of estrogen on parvalbumin (PV) levels in cardiac myocytes of ovariectomized rats, which is a model system for postmenopausal woman. Parvalbumin acts as a relaxing factor in cardiac myocytes. Adult female Wistar rats, 12 weeks old, were randomly divided into 5 groups of 10: sham-operated (SHAM), ovariectomized (OVX), and OVX receiving estrogen replacement of 10 mu g/kg (Es10), 20 mu g/kg (Es20) and 40 mu g/kg (Es40). After 10 weeks, serum estrogen levels were measured and the alpha and beta estrogen receptors in cardiac myocytes were investigated by immunohistochemistry. PV levels were examined by immunohistochemistry and Western blot analysis. Cardiac myocytes of all animals showed strong staining intensities for a immunoreactive (Es alpha-ir), but weak staining for beta immunoreactive (Es beta-ir) estrogen receptors. The Es alpha-ir was reduced in the cardiac myocytes of the OVX groups, but increased in the Es10, Es20 and Es40 groups. We therefore suggest that estrogen effects are mediated via Es a receptors rather than Es beta receptors in female rat hearts. Estrogen and PV immunoreactive (PV-ir) levels and the intensity of the PV band observed in the OVX group were less than those of the SHAM group. In the Es10, Es20 and Es40 groups, the increased intensity of the PV-ir and PV bands correlated with the increased estrogen levels. The low PV levels in cardiac myocytes induced by low estrogen were restored by estrogen replacement therapy. Therefore a reduction of PV may lead to diastolic dysfunction in menopause.

• 出版日期2012