Nutr Res Pract.  2017 Oct;11(5):373-380. 10.4162/nrp.2017.11.5.373.

Corn silk extract improves benign prostatic hyperplasia in experimental rat model

• Kim SR
• Ha AW
• Choi HJ
• Kim SL
• Kang HJ
• Kim MH
• Kim WK

• KMID: 2390129
• DOI: http://doi.org/10.4162/nrp.2017.11.5.373

Abstract

BACKGROUND/OBJECTIVES
This study was conducted to investigate the effect of a corn silk extract on improving benign prostatic hyperplasia (BPH).
MATERIALS/METHODS
The experimental animals, 6-week-old male Wistar rats, were divided into sham-operated control (Sham) and experimental groups. The experimental group, which underwent orchiectomy and received subcutaneous injection of 10 mg/kg of testosterone propionate to induce BPH, was divided into a Testo Only group that received only testosterone, a Testo+Fina group that received testosterone and 5 mg/kg finasteride, a Testo+CSE10 group that received testosterone and 10 mg/kg of corn silk extract, and a Testo+CSE100 group that received testosterone and 100 mg/kg of corn silk extract. Prostate weight and concentrations of dihydrotestosterone (DHT), 5α-reductase 2 (5α-R2), and prostate specific antigen (PSA) in serum or prostate tissue were determined. The mRNA expressions of 5α-R2 and proliferating cell nuclear antigen (PCNA) in prostate tissue were also measured.
RESULTS
Compared to the Sham group, prostate weight was significantly higher in the Testo Only group and decreased significantly in the Testo+Fina, Testo+CSE10, and Testo+CSE100 groups (P < 0.05), results that were consistent with those for serum DHT concentrations. The concentrations of 5α-R2 in serum and prostate as well as the mRNA expression of 5α-R2 in prostate were significantly lower in the Testo+Fina, Testo+CSE10, and Testo+CSE100 groups than that in the Testo Only group (P < 0.05). Similarly, the concentrations of PSA in serum and prostate were significantly lower in the Testo+Fina, Testo+CSE10, and Testo+CSE100 groups (P < 0.05) than in the Testo Only group. The mRNA expression of PCNA in prostate dose-independently decreased in the Testo+CSE-treated groups (P < 0.05).
CONCLUSIONS
BPH was induced through injection of testosterone, and corn silk extract treatment improved BPH symptoms by inhibiting the mRNA expression of 5α-R2 and decreasing the amount of 5α-R2, DHT, and PSA in serum and prostate tissue.

Keyword

Prostate; testosterone; Zea mays; finasteride; maysin

MeSH Terms

Animals
Dihydrotestosterone
Finasteride
Humans
Injections, Subcutaneous
Male
Models, Animal*
Orchiectomy
Proliferating Cell Nuclear Antigen
Prostate
Prostate-Specific Antigen
Prostatic Hyperplasia*
Rats*
Rats, Wistar
RNA, Messenger
Silk*
Testosterone
Testosterone Propionate
Zea mays*
Dihydrotestosterone
Finasteride
Proliferating Cell Nuclear Antigen
Prostate-Specific Antigen
RNA, Messenger
Silk
Testosterone
Testosterone Propionate

Figure

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  Fig. 1 Experimental design

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  Fig. 2 Effects of corn silk extract on prostate weights. Sham: corn oil + ethanol injection and distilled water oral intake; Testo Only: testosterone injection (10 mg/kg) and distilled water oral intake; Testo+Fina: testosterone injection (10 mg/kg) and finasteride (5 mg/kg) oral intake; Testo+CSE10: testosterone injection (10 mg/kg) and corn silk extract (10 mg/kg) oral intake; Testo+CSE100: testosterone injection (10 mg/kg) and corn silk extract (100 mg/kg) oral intake. Different letters indicate significant differences among group at α = 0.05 as determined by Duncan's multiple range test.

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  Fig. 3 Hematoxylin-eosin (H&E) staining of prostate. Sham: corn oil + ethanol injection and distilled water oral intake; Testo Only: testosterone injection (10 mg/kg) and distilled water oral intake; Testo+Fina: testosterone injection (10 mg/kg) and finasteride (5 mg/kg) oral intake; Testo+CSE10: testosterone injection (10 mg/kg) and corn silk extract (10 mg/kg) oral intake; Testo+CSE100: testosterone injection (10 mg/kg) and corn silk extract (100 mg/kg) oral intake. (×20)

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  Fig. 4 Effect of corn silk extract on serum dihydrotestosterone (DHT) concentration. Sham: corn oil + ethanol injection and distilled water oral intake; Testo Only: testosterone injection (10 mg/kg) and distilled water oral intake; Testo+Fina: testosterone injection (10 mg/kg) and finasteride (5 mg/kg) oral intake; Testo+CSE10: testosterone injection (10 mg/kg) and corn silk extract (10 mg/kg) oral intake; Testo+CSE100: testosterone injection (10 mg/kg) and corn silk extract (100 mg/kg) oral intake. Different letters indicate significant differences among group at α = 0.05 as determined by Duncan's multiple range test.

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  Fig. 5 Effect of corn silk extract on 5α-reductase 2 (5α-R2) concentrations and mRNA expression. Sham: corn oil + ethanol injection and distilled water oral intake; Testo Only: testosterone injection (10 mg/kg) and distilled water oral intake; Testo+Fina: testosterone injection (10 mg/kg) and finasteride (5 mg/kg) oral intake; Testo+CSE10: testosterone injection (10 mg/kg) and corn silk extract (10 mg/kg) oral intake; Testo+CSE100: testosterone injection (10 mg/kg) and corn silk extract (100 mg/kg) oral intake. A: 5α-R2 concentration in prostate in serum, B: 5α-R2 concentration in prostate, C: 5α-R2 mRNA expression in prostate. Different letters indicate significant differences among group at α = 0.05 as determined by Duncan's multiple range test.

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  Fig. 6 Effect of corn silk extract on prostate-specific antigen (PSA) concentrations in serum and prostate. Sham: corn oil + ethanol injection and distilled water oral intake; Testo Only: testosterone injection (10 mg/kg) and distilled water oral intake; Testo+Fina: testosterone injection (10 mg/kg) and finasteride (5 mg/kg) oral intake; Testo+CSE10: testosterone injection (10 mg/kg) and corn silk extract (10 mg/kg) oral intake; Testo+CSE100: testosterone injection (10 mg/kg) and corn silk extract (100 mg/kg) oral intake. A: serum, B: prostate. Different letters indicate significant differences among group at α = 0.05 as determined by Duncan's multiple range test.

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  Fig. 7 Effect of corn silk extract on mRNA expression of proliferating cell nuclear antigen (PCNA) in prostate. Sham: corn oil + ethanol injection and distilled water oral intake; Testo Only: testosterone injection (10 mg/kg) and distilled water oral intake; Testo+Fina: testosterone injection (10 mg/kg) and finasteride (5 mg/kg) oral intake; Testo+CSE10: testosterone injection (10 mg/kg) and corn silk extract (10 mg/kg) oral intake; Testo+CSE100: testosterone injection (10 mg/kg) and corn silk extract (100 mg/kg) oral intake. Different letters indicate significant differences among group at α = 0.05 as determined by Duncan's multiple range test.

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