Icariside II reduces testosterone production by inducing necrosis in rat Leydig cells

The present study demonstrates that Icariside II (10, 20, and 40 µM) reduced Leydig cell testosterone production and cell viability in a concentration- and time-dependent manner. Hoechst 33342/propidium iodide staining indicated that no morphological changes in Leydig cell nuclear chromatin occurred, caspase-3 expression also showed no significant change, but cell death was caused by the 10-µM Icariside II treatment. Furthermore, a significant reduction in NAD(+) levels was observed following Icariside II exposure (10, 20, and 40 µM). Cell death was avoided when Icariside II treated cells were incubated with extracellular NAD(+) (5 and 10 mM). Moreover, the addition of NAD(+) (5 and 10 mM) could restore ATP production and prevent cell death. The results suggest that Icariside II can reduce testosterone production by inducing necrosis, but not apoptosis, in rat Leydig cells. This mechanism may also account for the Icariside II induced depletion of NAD(+) and ATP levels.