Gonadal steroids do not affect apolipoprotein E expression in aging mouse cerebral cortex

Abstract

The allelic variant of apolipoprotein (Apo) E4 is a known risk factor for the development of most common late onset form of Alzheimer's disease (AD). As aging is associated with reduced circulating level of gonadal steroid hormones, hormone replacement therapies have been used for the possible treatment of AD. Both estrogen and testosterone have beneficial effects on brain due to interaction with apoE, but the underlying mechanism is still not clear. In this article, we report the effects of gonadectomy and hormone supplementation on apoE protein level in male and female mouse cerebral cortex during normal aging. We could not get any effect of gonadectomy and estradiol or testosterone treatment in adult and old mice of either sex. This suggests that during normal aging apoE protein level is not affected due to steroid hormone withdrawal or supplementation in the mouse cerebral cortex.

Fig. 1

Western blot analysis of apoE in the cerebral cortex of male mice. a Western blot of apoE in different groups. Signal intensity for apoE was normalized against signal intensity for ß-tubulin III. b Histogram representing mean of integrated density value (IDV) from three independent experiments on Y-axis and different groups on X-axis. I intact, G gonadectomized, T gonadectomized with testosterone treated, and E gonadectomized with estradiol treated

Fig. 2

Western blot analysis of apoE in the cerebral cortex of female mice. a Western blot of apoE in different groups. Signal intensity for apoE was normalized against signal intensity for ß-tubulin III. b Histogram representing mean of integrated density value (IDV) from three independent experiments on Y-axis and different groups on X-axis. I intact, G gonadectomized, T gonadectomized with testosterone treated, and E gonadectomized with estradiol treated