Korean red ginseng extract rejuvenates testicular ineffectiveness and sperm maturation process in aged rats by regulating redox proteins and oxidative defense mechanisms.

Distortion of intracellular oxidant and antioxidant balances appears to be a common feature that underlies in age-related male sexual impairment. Therefore regulating oxidative defense mechanisms might be an ideal approach in improving male sexual dysfunctions. In the present study, the effect of Korean red ginseng aqueous extract (KRG) on age-induced testicular dysfunction in rats was investigated. KRG (200mg/kg) mixed with regular pellet diet was administered orally for six months and the morphological, spermatogenic and antioxidant enzyme status in testis of aged rats (18months) were evaluated. Data indicated a significant change in morphology and decrease in spermatogenesis-related parameters in aged rats (AC) compared with young rats (YC). Sperm number, germ cell count, Sertoli cell count and Sertoli cell index were significantly (p<0.05) restored in KRG-treated aged rat groups (G-AC). Further the increased lipid peroxidation as measured by malondialdehyde (p<0.05), and altered enzymatic (superoxide dismutase, glutathione peroxidase, glutathione S-transferase, glutathione reductase and catalase) and non-enzymatic (reduced glutathione, ascorbic acid and α-tocopherol) antioxidants (p<0.05) were attenuated by KRG treatment in aged rats to near normal levels as in YC groups. Furthermore, proteomic analysis demonstrated differential expression of selected proteins such as phosphatidylinositol transfer protein, fatty acid binding protein-9, triosephosphate isomerase-1 and aldehyde (aldose) reductase-1in aged rats was significantly (p<0.05) protected by KRG treatment. In conclusion, long-term administration of KRG restored aging-induced testicular ineffectiveness in rats by modulating redox proteins and oxidative defense mechanisms.

Pectinase-treated Panax ginseng extract (GINST) rescues testicular dysfunction in aged rats via redox-modulating proteins.

The root of Panax ginseng improves testicular function both in humans and animals. However, the molecular mechanism by which ginseng exerts this effect has not been elucidated. Changes in protein expression in the rat testis in response to a pectinase-treated P. ginseng extract (GINST) were identified using 2-dimensional electrophoresis (2-DE) and MALDI-TOF/TOF MS. Number of sperm, Sertoli cells and germ cells, and the Sertoli Cell Index decrease in the testis of aged rats (AR) relative to young control rats (YCR). However, those parameters were completely restored in GINST-treated AR (GINST-AR). A proteomic analysis identified 14 proteins that were differentially expressed between vehicle-treated AR (V-AR) and GINST-AR. Out of these, the expression of glutathione-S-transferase (GST) mu5 and phospholipid hydroperoxide (PH) glutathione peroxidase (GPx) was significantly up-regulated in GINST-AR compared to V-AR. The activity of GPx and GST, as well as the expression of glutathione, in the testis of GINST-AR was higher than that in V-AR. The levels of lipid peroxidation (LPO) increased in AR compared with YCR, but this change was reversed by GINST-AR. These results suggest that the administration of GINST enhances testicular function by elevating GPx and GST activity, thus resulting in increased glutathione, which prevents LPO in the testis.

ß-Hydroxybutyrate modulates N-type calcium channels in rat sympathetic neurons by acting as an agonist for the G-protein-coupled receptor FFA3.

Free fatty acids receptor 3 (FFA3, GPR41) and 2 (FFA2, GPR43), for which the short-chain fatty acids (SCFAs) acetate and propionate are agonist, have emerged as important G-protein-coupled receptors influenced by diet and gut flora composition. A recent study (Kimura et al., 2011) demonstrated functional expression of FFA3 in the rodent sympathetic nervous system (SNS) providing a potential link between nutritional status and autonomic function. However, little is known of the source of endogenous ligands, signaling pathways, or effectors in sympathetic neurons. In this study, we found that FFA3 and FFA2 are unevenly expressed in the rat SNS with higher transcript levels in prevertebral (e.g., celiac-superior mesenteric and major pelvic) versus paravertebral (e.g., superior cervical and stellate) ganglia. FFA3, whether heterologously or natively expressed, coupled via PTX-sensitive G-proteins to produce voltage-dependent inhibition of N-type Ca(2+) channels (Cav2.2) in sympathetic neurons. In addition to acetate and propionate, we show that ß-hydroxybutyrate (BHB), a metabolite produced during ketogenic conditions, is also an FFA3 agonist. This contrasts with previous interpretations of BHB as an antagonist at FFA3. Together, these results indicate that endogenous BHB levels, especially when elevated under certain conditions, such as starvation, diabetic ketoacidosis, and ketogenic diets, play a potentially important role in regulating the activity of the SNS through FFA3.