In vitro and in vivo evaluation of tissue-cultured mountain ginseng on penile erection

Abstract

Background: Progressed tissue culture techniques have allowed us to easily obtain mass products of tissue-cultured mountain ginseng over 100 yr old (TCMG-100). We investigated the effects of TCMG-100 extract on erectile function using in vitro and in vivo studies.

Methods: To examine the relaxation effects and mechanisms of action of TCMG-100 on rabbit cavernosal strips evaluated in an organ bath. To investigate the long-term treatment effect of TCMG-100, 8-wk administration was performed. After administration of TCMG-100, intracavernosal pressure, cyclic guanosine monophosphate and nitric oxide (NO) levels of cavernosal tissue, serum testosterone level, histological observation of collagen fiber, endothelium, smooth muscle cell, and transforming growth factor-β1 were investigated.

Results: TCMG-100 extract displayed dose-dependent relaxation effects on precontracted rabbit corporal smooth muscle. The TCMG-100-induced relaxation was significantly reduced by removing the endothelium, and treatment with an NO synthase inhibitor or NO scavenger. Eight weeks of TCMG-100 administration increased intracavernosal pressure in a rat model. The levels of cyclic guanosine monophosphate and NO in the corpus callosum and serum testosterone level were also increased by TCMG-100 treatment. Furthermore, histological evaluation of collagen, smooth muscle, and endothelium showed increases in endothelium and smooth muscle, and a decrease in transforming growth factor-β1 expression.

Conclusion: These relaxation effects on corporal smooth muscle and increased erectile function suggest that TCMG-100 might be used as an alternative herbal medicine to improve erectile function.

Keywords: corpus cavernosum; erectile function; mountain ginseng; nitric oxide; smooth muscle.

Fig. 1

Representative tracing of tissue-cultured mountain ginseng over 100 yr old effects on isolated rabbit corpus cavernosum muscle strips submaximally precontracted by phenylephrine. Tissue-cultured mountain ginseng over 100 yr old relaxed precontracted muscle strip in a dose-dependent fashion. Values represent the mean ± SD of mean and are expressed as percent relaxation (n = 8). TCMG-100, tissue-cultured mountain ginseng over 100 yr old.

Fig. 2

Effects of tissue-cultured mountain ginseng over 100 yr old pretreatment on phenylephrine (PHE)-induced contraction in rabbit corpus cavernosum muscle strips. The contractile response of the isolated cavernosal muscle strips to PHE was significantly inhibited by tissue-cultured mountain ginseng over 100 yr old pretreatment in a dose-dependent fashion. Values represent mean ± SD of mean and are expressed as the percentage of the initial contraction induced by PHE (n = 7). TCMG-100, tissue-cultured mountain ginseng over 100 yr old.

Fig. 3

Effects of various treatments on tissue-cultured mountain ginseng over 100 yr old-induced relaxation in the phenylephrine-induced precontracted muscle strips. The relaxation effects of tissue-cultured mountain ginseng over 100 yr old were significantly inhibited by endothelial disruption and by pretreatment with N-nitro-L-arginine (nitric oxide synthase inhibitor) or pyrogallol (nitric oxide scavenger). Values represent the mean ± SD of mean and are expressed as percentage of the relaxation. * p < 0.05 compared with the control group (n = 8). De-endo, endothelial disruption; MB, methylene blue; NNA, N-nitro-L-arginine; TCMG-100, tissue-cultured mountain ginseng over 100 yr old.

Fig. 4

Effects of tissue-cultured mountain ginseng over 100 yr old (TCMG-100). (A) Effects on maximal intracavernosal pressure/maximal arterial pressure ratio. (B) Effects on cyclic guanosine monophosphate. (C) Effects on nitric oxide levels. (D) Effects on serum testosterone. The ratio of maximal intracavernosal pressure/maximal arterial pressure with cavernosal nerve electro-stimulation after 8 wk of TCMG-100 administration was significantly increased compared with control group. The cyclic guanosine monophosphate levels and nitric oxide levels in the TCMG-100 treatment groups were significantly increased compared with those in the control group. The serum TT levels in the TCMG-100 treatment groups were significantly increased. Data are expressed as the mean ± SD. * p < 0.05 compared with the control group (n = 8). cGMP, cyclic guanosine monophosphate; MIP/MAP, maximal intracavernosal pressure/maximal arterial pressure; NO, nitric oxide; TCMG-100, tissue-cultured mountain ginseng over 100 yr old.

Fig. 5

The distribution of collagen fibers in hematoxylin and eosin or Masson's trichrome stained cavernous tissue. (A) Control group. (B) Tissue-cultured mountain ginseng over 100 yr old (250 mg/kg). (C) tissue-cultured mountain ginseng over 100 yr old (500 mg/kg). (D) Quantitative analysis of collagen (blue) in the corpus cavernous body was performed with an image analyzer. Scale bars = 50 μm. Data are expressed as the mean ± SD. H&E, hematoxylin and eosin; TCMG-100, tissue-cultured mountain ginseng over 100 yr old.

Fig. 6

Immunohistochemical localization of smooth muscle cells in cavernous tissue. (A) Control group. (B) Tissue-cultured mountain ginseng over 100 yr old (250 mg/kg). (C) Tissue-cultured mountain ginseng over 100 yr old (500 mg/kg). (D) Quantitative analysis of smooth muscle (brown) in the corpus cavernous body was performed with an image analyzer. Data are expressed as the mean ± SD. Scale bars = 50 μm. * p < 0.05 compared with the control group. TCMG-100, tissue-cultured mountain ginseng over 100 yr old.

Fig. 7

Immunohistochemical localization of endothelial cells in cavernous tissue. (A) Control group. (B) Tissue-cultured mountain ginseng over 100 yr old (250 mg/kg). (C) Tissue-cultured mountain ginseng over 100 yr old (500 mg/kg). (D) Quantitative analysis of endothelium (brown) in corpus cavernous body was performed with an image analyzer. Data are expressed as the mean ± SD. Scale bars = 50 μm (left side) or 20 μm (right side). * p < 0.05 compared with the control group. TCMG-100, tissue-cultured mountain ginseng over 100 yr old.

Fig. 8

Effects of tissue-cultured mountain ginseng over 100 yr old on transforming growth factor-β1 expression in corpus cavernosal tissue. The relative or fold-increases of transforming growth factor-β1 expression (44 kDa or 13 kDa) were significantly decreased in the tissue-cultured mountain ginseng over 100 yr old treatment groups compared with control group. Data are expressed as the mean ± SD. * p < 0.05 compared with the control group. TCMG-100, tissue-cultured mountain ginseng over 100 yr old; TGF-β1, transforming growth factor-β1.