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Polycan, a β -glucan from Aureobasidium pullulans SM-2001, mitigates ovariectomy-induced osteoporosis in rats

View Article: PubMed Central - PubMed

ABSTRACT

The present study aimed to investigate the protective effects of Polycan, a β-glucan from Aureobasidium pullulans SM-2001, in a rat model of ovariectomy-induced osteoporosis. Ovariectomized (OVX) rats were orally administered 31.25, 62.5 or 125 mg/kg/day Polycan for 126 days, and alterations in body weight, bone mineral content, bone mineral density, failure load, histological profiles and histomorphometric indices were analyzed. In particular, serum levels of osteocalcin, bone-specific alkaline phosphatase (bALP), calcium and phosphorus, and the urine deoxypyridinoline/creatinine ratio, were measured. Furthermore, the femur, tibia and lumbar vertebrae were harvested from all rats, and histomorphometrical analyses were conducted in order to assess the mass and structure of the bones, and the rates of bone resorption and formation. One group of rats was treated with alendronate, which served as the reference drug. The results of the present study suggested that Polycan treatment was able to inhibit ovariectomy-induced alterations in bone resorption and turnover in a dose-dependent manner. In addition, the serum expression levels of bALP and all histomorphometrical indices for bone formation were markedly increased in the Polycan-treated groups. These results indicated that Polycan was able to preserve bone mass and strength, and increase the rate of bone formation in OVX rats; thus suggesting that Polycan may be considered a potential effective anti-osteoporosis agent.

No MeSH data available.


Fluorescent histological profiles of the femur of the (A and B) sham, (C and D) ovariectomized (OVX) control and (E and F) alendronate-treated groups, and the (G and H) 31.25, (I and J) 62.5 and (K and L) 125 mg/kg Polycan-treated groups. The mineral apposition rate (MAR) was markedly increased in the trabecular and cortical bone regions of the femur in the Polycan-treated rats, in a dose-dependent manner, as compared with the OVX control group. Conversely, the MAR was markedly decreased in both bone regions of the femur in the alendronate-treated rats, as compared with the OVX control group. A, C, E, G, I and K display trabecular bone regions (magnification, ×200); B, D, F, H, J and L display cortical bone regions (magnification, ×200). Arrows indicate the tetracycline and calcein labeled lines. The distant between the arrows represents the MAR over a 10-day period.
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f2-etm-0-0-3485: Fluorescent histological profiles of the femur of the (A and B) sham, (C and D) ovariectomized (OVX) control and (E and F) alendronate-treated groups, and the (G and H) 31.25, (I and J) 62.5 and (K and L) 125 mg/kg Polycan-treated groups. The mineral apposition rate (MAR) was markedly increased in the trabecular and cortical bone regions of the femur in the Polycan-treated rats, in a dose-dependent manner, as compared with the OVX control group. Conversely, the MAR was markedly decreased in both bone regions of the femur in the alendronate-treated rats, as compared with the OVX control group. A, C, E, G, I and K display trabecular bone regions (magnification, ×200); B, D, F, H, J and L display cortical bone regions (magnification, ×200). Arrows indicate the tetracycline and calcein labeled lines. The distant between the arrows represents the MAR over a 10-day period.

Mentions: Relatively well-developed and compact trabecular and cortical bone regions were observed in the femur of the sham control group rats. Conversely, the OVX control group exhibited a histological profile that was typical for osteoporosis, including marked reductions in the trabecular and cortical bone masses, and increased levels of connective tissue in the periosteum of the cortical bone due to the resorption of osteoid tissues. Alterations in the bone histomorphometry were markedly decreased in the Polycan-treated groups, particularly within the cortical bone, as compared with the OVX control group (Fig. 1). In the OVX control group, an increased MAR, as indicated by the distance between the tetracycline and calcein labeling regions, was observed in the cortical and trabecular bone regions, as compared with the sham control group. Conversely, a dose-dependent increase in MAR was detected in the cortical and trabecular bone regions of the Polycan-treated groups, as compared with the OVX control group. In the alendronate-treated group, the MAR in all three bones tested was markedly decreased compared with the OVX control group (Fig. 2).


Polycan, a β -glucan from Aureobasidium pullulans SM-2001, mitigates ovariectomy-induced osteoporosis in rats
Fluorescent histological profiles of the femur of the (A and B) sham, (C and D) ovariectomized (OVX) control and (E and F) alendronate-treated groups, and the (G and H) 31.25, (I and J) 62.5 and (K and L) 125 mg/kg Polycan-treated groups. The mineral apposition rate (MAR) was markedly increased in the trabecular and cortical bone regions of the femur in the Polycan-treated rats, in a dose-dependent manner, as compared with the OVX control group. Conversely, the MAR was markedly decreased in both bone regions of the femur in the alendronate-treated rats, as compared with the OVX control group. A, C, E, G, I and K display trabecular bone regions (magnification, ×200); B, D, F, H, J and L display cortical bone regions (magnification, ×200). Arrows indicate the tetracycline and calcein labeled lines. The distant between the arrows represents the MAR over a 10-day period.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4998138&req=5

f2-etm-0-0-3485: Fluorescent histological profiles of the femur of the (A and B) sham, (C and D) ovariectomized (OVX) control and (E and F) alendronate-treated groups, and the (G and H) 31.25, (I and J) 62.5 and (K and L) 125 mg/kg Polycan-treated groups. The mineral apposition rate (MAR) was markedly increased in the trabecular and cortical bone regions of the femur in the Polycan-treated rats, in a dose-dependent manner, as compared with the OVX control group. Conversely, the MAR was markedly decreased in both bone regions of the femur in the alendronate-treated rats, as compared with the OVX control group. A, C, E, G, I and K display trabecular bone regions (magnification, ×200); B, D, F, H, J and L display cortical bone regions (magnification, ×200). Arrows indicate the tetracycline and calcein labeled lines. The distant between the arrows represents the MAR over a 10-day period.
Mentions: Relatively well-developed and compact trabecular and cortical bone regions were observed in the femur of the sham control group rats. Conversely, the OVX control group exhibited a histological profile that was typical for osteoporosis, including marked reductions in the trabecular and cortical bone masses, and increased levels of connective tissue in the periosteum of the cortical bone due to the resorption of osteoid tissues. Alterations in the bone histomorphometry were markedly decreased in the Polycan-treated groups, particularly within the cortical bone, as compared with the OVX control group (Fig. 1). In the OVX control group, an increased MAR, as indicated by the distance between the tetracycline and calcein labeling regions, was observed in the cortical and trabecular bone regions, as compared with the sham control group. Conversely, a dose-dependent increase in MAR was detected in the cortical and trabecular bone regions of the Polycan-treated groups, as compared with the OVX control group. In the alendronate-treated group, the MAR in all three bones tested was markedly decreased compared with the OVX control group (Fig. 2).

View Article: PubMed Central - PubMed

ABSTRACT

The present study aimed to investigate the protective effects of Polycan, a β-glucan from Aureobasidium pullulans SM-2001, in a rat model of ovariectomy-induced osteoporosis. Ovariectomized (OVX) rats were orally administered 31.25, 62.5 or 125 mg/kg/day Polycan for 126 days, and alterations in body weight, bone mineral content, bone mineral density, failure load, histological profiles and histomorphometric indices were analyzed. In particular, serum levels of osteocalcin, bone-specific alkaline phosphatase (bALP), calcium and phosphorus, and the urine deoxypyridinoline/creatinine ratio, were measured. Furthermore, the femur, tibia and lumbar vertebrae were harvested from all rats, and histomorphometrical analyses were conducted in order to assess the mass and structure of the bones, and the rates of bone resorption and formation. One group of rats was treated with alendronate, which served as the reference drug. The results of the present study suggested that Polycan treatment was able to inhibit ovariectomy-induced alterations in bone resorption and turnover in a dose-dependent manner. In addition, the serum expression levels of bALP and all histomorphometrical indices for bone formation were markedly increased in the Polycan-treated groups. These results indicated that Polycan was able to preserve bone mass and strength, and increase the rate of bone formation in OVX rats; thus suggesting that Polycan may be considered a potential effective anti-osteoporosis agent.

No MeSH data available.