The angiogenic effect of testosterone supplementation on brain of aged mice

Abstract

The aim of this study was to determine, by histological and molecular techniques, the effects of testosterone hormone treatment on angiogenesis in brain of aged mice. A total of 30 mice were used in 3 study groups: Sham operation group (Control), gonadectomy group (G) and gonadectomy and testosterone supplementation group (GTS). The capillary number and the inner diameter of larger capillary vessels in brain were measured by light microscope. The levels of VEGF (vascular endothelial growth factor) mRNA in brain tissues were determined by RT-PCR. After gonadectomy operation, capillary densities of brain decreased in male (P<0.05) but did not changed in female. Testosterone supplementation to gonadectomized aged mice caused a mild increase on capillary number in female brain but did not affect in male. Gonadectomy caused a decrease in VEGF mRNA levels of brain in male and female mice. Interestingly, testosterone replacement caused an important decrease (P<0.05) in the expression of VEGF of brain in male compared to control group whereas resulted with no change in female. The present results showed that testosterone hormone has different angiogenic effect on brain in male and female old mice. The gonadectomy operation in old male mice has a negative effect on angiogenic events. However, testosterone replacement in male was not sufficient to convert this change and did not increase angiogenesis.

Keywords

• angiogenesis
• testosterone
• old mice
• brain