Pine polyphenols from Pinus koraiensis prevent injuries induced by gamma radiation in mice

Abstract

Pine polyphenols (PPs) are bioactive dietary constituents that enhance health and help prevent diseases through antioxidants. Antioxidants reduce the level of oxidative damages caused by ionizing radiation (IR). The main purpose of this paper is to study the protective effect of PPs on peripheral blood, liver and spleen injuries in mice induced by IR. ICR (Institute of Cancer Research) male mice were administered orally with PPs (200 mg/kg b.wt.) once daily for 14 consecutive days prior to 7 Gy γ-radiations. PPs showed strong antioxidant activities. PPs significantly increased white blood cells, red blood cells and platelets counts. PPs also significantly reduced lipid peroxidation and increased the activities of superoxide dismutase, catalase and glutathione peroxidases, and the level of glutathione. PPs reduced the spleen morphologic injury. In addition, PPs inhibited mitochondria-dependent apoptosis pathways in splenocytes induced by IR. These results indicate that PPs are radioprotective promising reagents.

Keywords: Antioxidant; Apoptosis; Pine polyphenols; Redox; γ-radiation.

Figure 1. Antioxidant activities of PPs from Pinus koraiensis.

(A) DPPH free radical scavenging activity; (B) superoxide anion radical scavenging activity; (C) hydroxyl radical scavenging activity; (D) reducing power assay. Each value represents mean ± SD (repeat three times).

Figure 2

The radioprotective effect of different doses PPs pretreatment on spleen index (n = 6) in mice. The irradiation dose was 7 Gy. ^∗P < 0.05 vs Control, ^#P < 0.05 vs IR. n is number of mice.

Figure 3

The effect of PPs (200 mg/kg bwt/d) pretreatment on the levels of MDA on plasma (n = 10), liver (n = 10) and spleen (n = 6) in mice. The irradiation dose was 7 Gy. ^∗P < 0.05 vs Control, ^#P < 0.05 vs IR. n is number of mice.

Figure 4

The effect of PPs (200 mg/kg bwt/d) pretreatment on the levels of enzymatic and non-enzymatic antioxidants on plasma (n = 10), liver (n = 10) and spleen (n = 6) in mice. The irradiation dose was 7 Gy. (A) SOD; (B) CAT; (C) GSH-Px; (D) GSH. ^∗P < 0.05 vs Control, ^#P < 0.05 vs IR. n is number of mice.

Figure 5

Photomicrographs of spleen sections stained with hematoxylin and eosin staining. PPs were given at a dose of 200 mg/kg body weight daily for 14 consecutive days prior to irradiation (7 Gy). Spleen histology: magnification: 10×. (A) Spleens of mice with the Control are comprised of both red (RP) and white pulps (WP). (B) Spleens in mice with PPs. (C) Spleens in mice with IR. (D) Spleens of mice in mice with PPs + IR.

Figure 6

PPs (200 mg/kg bwt/d) inhibits the expression levels of Bax, cytochrome c and caspase-3 induced by irradiation (7 Gy) and inceases the expression levels of Bcl-2 in spleen (n = 6). (A) The expression of Bcl-2, Bax, cytochrome c and caspase-3 in spleen by Western blotting. (B) The expression level of Bcl-2. (C) The expression level of Bax. (D) The ratio of Bax/Bcl-2. (E) The expression level of cytochrome c. (F) The expression level of caspase-3. ^∗P < 0.05 vs Control, ^#P < 0.05 vs IR. n is number of mice.