Palmul-Tang, a Korean Medicine, Promotes Bone Formation via BMP-2 Pathway in Osteoporosis

Abstract

Osteoporosis is a common skeletal disease in post-menopausal women. Palmul-tang, an herbal medicine, has been treated for gynecological disease such as anemia, anorexia, anti-fatigue, unspecified menstruation and female infertility in East Asia. In this study, ameliorative effects of Palmul-tang soft extracts (PMT), a Korean Medicine, on osteoporosis were investigated. Ovariectomized (OVX) osteoporotic ICR mice were intragastrically administrated PMT for 4 weeks. The level of bone mineral density (BMD) was analyzed in bone tissues by dual X-ray absorptiometry. The bone medullary cavity and deposition of collagen were investigated by histological analysis. In addition, the BMP-2 signaling-related molecules, osteoblastic differentiation and formation markers, were determined in femoral tissues. The levels of BMD and bone mineral content were significantly increased in tibia, femurs and LV by treatment of PMT. PMT replenished bone marrow cavity and increased collagen deposition in bone marrow cells of femur. In addition, administration of PMT recovered serum ALP, bALP, osteocalcin and calcium levels in osteoporotic mice. Moreover, PMT treatment up-regulated the expressions of BMP-2, RUNX2 and OSX with its downstream factors, ALP, OPN and BSP-1, in the femoral tissues. Taken together, PMT restored the bone minerals and improvement of bone integrity by bone-forming BMP-2 signaling pathway. These results demonstrate that PMT could be an ameliorative agent for osteoporosis.

Keywords: BMP-2; bone integrity; osteoporosis; palmul-tang; traditional herbal medicine.

FIGURE 1

Effects of PMT on BMC and BMD in osteoporotic mice. Bone mineral content and bone mineral density of tibiae, femora and lumbar vertebrae were analyzed by DXA. (A) Levels of bone mineral content in tibia, femur and LV. (B) Levels of bone mineral density in tibia, femur and LV. Results are presented as mean ± standard error of the mean. ^# p < 0.05, ^## p < 0.01 and ^### p < 0.001 vs. Sham group; *p < 0.05, **p < 0.01 and ***p < 0.001 vs. OVX group. OVX, ovariectomized group; E2, 17β-estradiol group; PMT, Palmul-tang soft extracts; LV, lumbar vertebrae; BMC, bone mineral content; BMD, bone mineral density.

FIGURE 2

Effects of PMT on histological changes in femur. Evaluation of histological changes using hematoxylin and eosin staining for bone marrow cavity and picrosirius red staining for detecting deposition of collagen. Magnification of images were ×400. OVX, ovariectomized group; E2, 17β-estradiol group; PMT, Palmul-tang soft extracts.

FIGURE 3

Effects of PMT on bone specific markers in serum. Secretion of bone specific markers in serum was analyzed by ELISA. Results are presented as the mean ± standard error. ^## p < 0.01 and ^### p < 0.001 vs. Sham group; *p < 0.05 and **p < 0.01 vs. OVX group. OVX, ovariectomized group; E2, 17β-estradiol group; PMT, Palmul-tang soft extracts; ALP, alkaline phosphatase; bALP, bone-specific alkaline phosphatase.

FIGURE 4

Effects of PMT on osteoblastic differentiation initiation markers in femur. Osteoblastic differentiation initiation markers were analyzed by RT-PCR. Results are presented as the mean ± standard error. ^### p < 0.001 vs. Sham group; ***p < 0.001 vs. OVX group. OVX, ovariectomized group; E2, 17β-estradiol group; PMT, Palmul-tang soft extracts; BMP-2, bone morphogenetic protein 2; RUNX2, Runt-related transcription factor 2; OSX, osterix.

FIGURE 5

Effects of PMT on osteoblastic production markers in femur. Osteoblastic production markers were analyzed by RT-PCR. Results are presented as the mean ± standard error. ^### p < 0.001 vs. Sham group; ***p < 0.001 vs. OVX group. OVX, ovariectomized group; E2, 17β-estradiol group; PMT, Palmul-tang soft extracts; ALP, alkaline phosphatase; OPN, osteopontin; BSP-1, bone sialoprotein 1.