Background: Extractions of Lessertia frutescens (Lf)
are shown to have immune modulation, anti-inflammatory and antioxidant
properties. However, Lf is also cytotoxic, antiproliferative, and
pro-apoptotic in vitro. Furthermore, Lf extractions may
influence steroidogenesis. Nevertheless, the impact on Leydig cell function has
not previously been investigated. As tumor necrosis factor-alpha (TNF-) is known to cause Leydig cell
dysfunction under inflammatory conditions, it is further proposed that
Lf extracts may protect against the negative impact of TNF- on
Leydig cells. The aim of the study was to investigate the effect of an aqueous
Lessertia frutescens extract (LFE) on Leydig cells exposed to TNF-in vitro. Methods: Human chorionic gonadotrophin-stimulated TM3
Leydig cells were exposed for 24 h to (a) TNF- (0.1, 1, 10, 100 ng/mL),
(b) LFE (0.01, 0.1, 1, 10, 100 ng/mL), and (c) co-exposure to 10 ng/mL
TNF- and LFE (0.01, 0.1, 1, 10, 100 ng/mL). We analyzed cell
viability, cytotoxicity, caspase 3/7 activation, testosterone concentration, and
intracellular superoxide. Results: TNF- exposure decreased
cell viability, increased cytotoxicity, and caspase 3/7, with no significant
effect on intracellular superoxide in TM3 Leydig cells. When LFE
concentrations of 0.01–10 ng/mL were tested, we observed improved vitality and
reduced levels of caspase 3/7. At 100 ng/mL, LFE decreased viability and
increased cytotoxicity and caspase 3/7. However, LFE did not affect
intracellular superoxide. Furthermore, LFE protected against 10 ng/mL
TNF--induced cytotoxicity and apoptosis, except at the highest
concentration. LFE alone and in co-culture with 10 ng/mL TNF-
increased testosterone at high concentrations. Conclusions: In our TM3
Leydig cell model, LFE protected against TNF--induced
cytotoxicity and early apoptosis, except at the highest experimental
concentrations, where it was cytotoxic. These effects were not mediated through a
change in intracellular superoxide. Although further investigations are
warranted, aqueous LFE may protect against TNF--induced Leydig
cell dysfunction.