Lab Anim Res.  2018 Sep;34(3):111-117. 10.5625/lar.2018.34.3.111.

Inhibitory effects of Pycnogenol®, a pine bark extract, in a rat model of testosterone propionate-induced benign prostatic hyperplasia

• Ko JW
• Park SW
• Shin NR
• Kim WI
• Kim JC
• Shin IS
• Shin DH

• KMID: 2420823
• DOI: http://doi.org/10.5625/lar.2018.34.3.111

Abstract

Benign prostate hyperplasia (BPH) is a male reproductive disease that has gained increasing importance in recent years. The present study investigated whether Pycnogenol® (PYC), a standardized French maritime pine bark extract, could prevent BPH induced by testosterone propionate (TP) in rats. Male Sprague-Dawley rats were randomly divided into five groups of six rats. One group was used as a normal control rats and the other groups received subcutaneous injections of TP for 4 weeks to induce BPH. In the two treatment groups, PYC (20 or 40 mg/kg) was administered daily for 4 weeks by oral gavage concurrently with the induction of TP. All rats were sacrificed at the scheduled termination time, the prostates were weighed, and histopathologic examinations were conducted. Dihydrotestosterone (DHT) levels in serum and the prostate were measured, and the expression of proliferating cell nuclear antigen (PCNA) and Ki-67 proteins was investigated. BPH-treated animals showed increases in the relative weight of the prostate, higher concentrations of DHT in serum and the prostate, and higher expression of PCNA and Ki-67 in the prostate; in contrast, PYC-treated animals had significant reductions in these factors compared with the BPH animals. These findings indicated that PYC inhibited the development of BPH and that this was closely associated with a reduction in DHT concentration.

Keyword

Benign prostate hyperplasia; Pycnogenol; dihydrotestosterone; proliferating cell nuclear antigen; Ki-67

MeSH Terms

Animals
Dihydrotestosterone
Humans
Hyperplasia
Injections, Subcutaneous
Male
Models, Animal*
Proliferating Cell Nuclear Antigen
Prostate
Prostatic Hyperplasia*
Rats*
Rats, Sprague-Dawley
Testosterone Propionate
Testosterone*
Dihydrotestosterone
Proliferating Cell Nuclear Antigen
Testosterone
Testosterone Propionate

Figure

• 

  Figure 1 The effects of PYC on relative prostate weights in TP-treated rats. NC, corn oil injection (s.c.)+PBS (p.o.); BPH, TP (s.c.)+PBS (p.o.); Finasteride, TP (s.c.)+finasteride (10 mg/kg, p.o.); PYC-20, TP (s.c.)+PYC (20 mg/kg, p.o.); PYC-40, TP (s.c.)+PYC (40 mg/kg, p.o.). ##P<0.01 vs. the NC. *P<0.05 vs. the BPH. The values are expressed as the mean±SD (n=6).

• 

  Figure 2 The effects of PYC on (A) DHT concentration in the serum and (B) in the prostate. NC, corn oil injection (s.c.)+PBS (p.o.); BPH, TP (s.c.)+PBS (p.o.); Finasteride, TP (s.c.)+finasteride (10 mg/kg, p.o.); PYC-20, TP (s.c.)+PYC (20 mg/kg, p.o.); PYC-40, TP (s.c.)+PYC (40 mg/kg, p.o.). ##P<0.01 vs. the NC. **P<0.01 vs. the BPH. The values are expressed as the mean±SD (n=6).

• 

  Figure 3 The effects of PYC on prostate hyperplasia. The histological examination of prostate tissue was performed by using H&E staining. NC, corn oil injection (s.c.)+PBS (p.o.); BPH, TP (s.c.)+PBS (p.o.); Finasteride, TP (s.c.)+finasteride (10 mg/kg, p.o.); PYC-20, TP (s.c.)+PYC (20 mg/kg, p.o.); PYC-40, TP (s.c.)+PYC (40 mg/kg, p.o.). Arrows indicate the area of prostate hyperplasia. Scale bar=50 µm (×200).

• 

  Figure 4 The effects of PYC on the protein expression of Ki-67 in the prostate. The histological examination of prostate tissue was performed by using immunohistochemistry. NC, corn oil injection (s.c.)+PBS (p.o.); BPH, TP (s.c.)+PBS (p.o.); Finasteride, TP (s.c.)+finasteride (10 mg/kg, p.o.); PYC-20, TP (s.c.)+PYC (20 mg/kg, p.o.); PYC-40, TP (s.c.)+PYC (40 mg/kg, p.o.). ##P<0.01 vs. the NC. *, **P<0.05 and P<0.01 vs. the BPH, respectively. The values are expressed as the mean±SD (n=6). Scale bar=50 µm (×400).

• 

  Figure 5 The effects of PYC on the protein expression of PCNA. Images of the gel and relative ratio of PCNA expression (ratio of PCNA to β-actin). NC, corn oil injection (s.c.)+PBS (p.o.); BPH, TP (s.c.)+PBS (p.o.); Finasteride, TP (s.c.)+finasteride (10 mg/kg, p.o.); PYC-20, TP (s.c.)+PYC (20 mg/kg, p.o.); PYC-40, TP (s.c.)+PYC (40 mg/kg, p.o.). ##P<0.01 vs. the NC. **P<0.01 vs. the BPH. The values are expressed as the mean±SD (n=6).

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