Arabinoxylan rice bran (MGN-3/Biobran) provides protection against whole-body γ-irradiation in mice via restoration of hematopoietic tissues

Abstract

The aim of the current study is to examine the protective effect of MGN-3 on overall maintenance of hematopoietic tissue after γ-irradiation. MGN-3 is an arabinoxylan from rice bran that has been shown to be a powerful antioxidant and immune modulator. Swiss albino mice were treated with MGN-3 prior to irradiation and continued to receive MGN-3 for 1 or 4 weeks. Results were compared with mice that received radiation (5 Gy γ rays) only, MGN-3 (40 mg/kg) only and control mice (receiving neither radiation nor MGN-3). At 1 and 4 weeks post-irradiation, different hematological, histopathological and biochemical parameters were examined. Mice exposed to irradiation alone showed significant depression in their complete blood count (CBC) except for neutrophilia. Additionally, histopathological studies showed hypocellularity of their bone marrow, as well as a remarkable decrease in splenic weight/relative size and in number of megakaryocytes. In contrast, pre-treatment with MGN-3 resulted in protection against irradiation-induced damage to the CBC parameters associated with complete bone marrow cellularity, as well as protection of the aforementioned splenic changes. Furthermore, MGN-3 exerted antioxidative activity in whole-body irradiated mice, and provided protection from irradiation-induced loss of body and organ weight. In conclusion, MGN-3 has the potential to protect progenitor cells in the bone marrow, which suggests the possible use of MGN-3/Biobran as an adjuvant treatment to counteract the severe adverse side effects associated with radiation therapy.

Keywords: Biobran; MGN-3; hematopoeitic cells; radiation.

Fig. 1.

RBC series in mice under different treatments at 1 and 4 weeks post-irradiation. A) RBC count, B) hemoglobin content (Hb), and C) hematocrit (Hct) readings at 1 and 4 weeks after initial treatment. Number of mice per group is 6–9. One asterisk indicates significant difference from control group at the 0.05 level. Two asterisks indicate significant difference from the control group at the 0.01 level. One dagger indicates significant difference from the irradiation group at the 0.05 level. Two daggers indicate significant difference from the irradiation group at the 0.01 level (% difference from the control group).

Fig. 2.

WBC series in mice under different treatments at 1 and 4 weeks post-irradiation. A) Total WBC count. The percent B) lymphocytes, C) monocytes, and D) neutrophils were determined at 1 and 4 weeks after initial treatment. Number of mice per group is 6–9. Two asterisks indicate significant difference from the corresponding control group at the 0.01 level. One dagger indicates significant difference from the irradiation group at the 0.05 level. Two daggers indicate significant difference from the irradiation group at the 0.01 level (% difference from the control group).

Fig. 3.

Platelet content in mice under different treatments at 1 and 4 weeks post-irradiation. Number of mice per group is 6–9. One asterisk indicates significant difference from the corresponding control group at the 0.05 level. Two asterisks indicate significant difference from the corresponding control group at the 0.01 level. Two daggers indicate significant difference from the irradiation group at the 0.01 level (% difference from the control group).

Fig. 4.

Histological sections of bone marrow from mice exposed to γ-irradiation, with or without treatment of MGN-3, at 1 and 4 weeks post-irradiation. Each cross-section contains an enlarged image. A) Control group, no treatment with irradiation or MGN-3 (100% marrow cellularity). B) Mice treated with MGN-3 alone (100% marrow cellularity). C) Mice exposed to irradiation alone, 1 week post-irradiation (marked decreased to absent marrow cellularity). D) Mice treated with MGN-3 and exposed to irradiation, 1 week post-irradiation (100% marrow cellularity). E) Mice exposed to irradiation alone, 4 weeks post-irradiation (partial recovery of bone marrow cellularity). F) Mice treated with MGN-3 and exposed to irradiation, 4 weeks post-irradiation (80% marrow cellularity).

Fig. 5.

Histological sections of spleens from mice exposed to irradiation, with or without treatment with MGN-3, at 1 week post-irradiation. Cross-sections (A–D left panel) of the spleens and higher magnifications of each (A′–D′ right panel). A) Control group, no exposure to irradiation or treatment with MGN-3. B) Mice treated with MGN-3 alone. C) Mice exposed to irradiation alone. D) Mice treated with MGN-3 and exposed to irradiation. Please notice the yellow arrows pointing to the megakaryocytes.

Fig. 6.

Changes of spleen (weight/relative size) from mice exposed to γ-irradiation, with or without treatment with MGN-3, at 1 and 4 weeks post-irradiation. Two asterisks indicate significant difference from the corresponding control at the 0.01 level. One dagger indicates significant difference from the corresponding irradiation group at the 0.05 level. Two daggers indicate significant difference from the corresponding irradiation group at the 0.01 level (% difference from the control group). The data are the mean ± SEM from 6–9 mice. Each of the photos is representative of the mice spleens in each group (comprised of 6–9 mice).

Fig. 7.

Effects of MGN-3 treatment on A) MDA content (µmol/g wet tissue), and B) GSH content (mg/g wet tissue) in spleens of mice at 1 and 4 weeks post-irradiation. Each value represents the mean ± SEM of six mice/group. One asterisk indicates significant difference from the corresponding irradiation group at the 0.05 level. Two asterisks indicate significant difference from the corresponding control group at the 0.01 level. One dagger indicates significant difference from the corresponding irradiated group at the 0.01 level.