The purpose of this study was to verify the effect of cordycepin on ovariectomized osteopenic rats. Fifty Wistar female rats used were divided into 5 groups: (1) sham-operation rats (control), (2) ovariectomized (OVX) rats with osteopenia, and (3) OVX’d rats with osteopenia treated with cordycepin (5 mg, 10 mg, and 20 mg) for 8 weeks. After the rats were treated orally with cordycepin, serum alkaline phosphatase (ALP), tartrate resistant acid phosphatase (TRAP), serum osteocalcin (OC), homocysteine (HCY) , C-terminal crosslinked telopeptides of collagen type I (CTX) level, and oxidative stress were examined, respectively. The femoral neck was used for mechanical compression testing. At the same time, we further investigated the effect of cordycepin
Osteoporosis is a major concern in public health care and the disease has severe consequences if untreated [
The herbal kingdom is a wide field to search for natural effective osteoporosis protective agent that has no side effects. As potential alternative treatments for osteoporosis, the preventive and therapeutic effects of natural products derived from plants have been reported [
Wistar rats (weighing
Cordycepin with 98% purification was obtained following the extraction and separation using a column chromatographic method [
Fifty rats were randomly divided into five groups of animals, four ovariectomized (OVX) and another given a sham-operation (control). Then groups 1 (sham) and 2 (OVX) were treated orally with 10 mL of saline; group 3, group 4, and group 5 were treated orally with cordycepin (5 mg, 10 mg, and 20 mg) for 8 weeks, respectively. Cordycepin was dissolved in distilled water and administrated orally twice daily using a feeding needle for 21 days, and control group received double distilled water instead of cordycepin. Body weight of the animals was recorded weekly.
On the last day of treatment and necropsy, blood was collected from dorsal aorta under ether anesthesia. After centrifugation, serum was harvested and kept at −20°C until analysis. The femoral neck was processed for mechanical testing. The entire fifth lumbar vertebrae and one tibia were processed for histology.
The mechanical strength of the femoral neck was measured by applying a vertical load to the femoral head using a Shimadzu EZ-1 pressure system. The fracture load was recorded at the peak force as Newton (N) at the point that the femoral neck fractured [
The tibia and the lumbar vertebrae were decalcified in formic acid, embedded in paraffin, and longitudinally sectioned. Histomorphometric analyses were made by tracing the section image onto a digitizing platen with the aid of a camera lucida attachment on the microscope and Osteomeasure bone analysis software. To reveal osteoclasts, sections were stained for immunoreactivity to cathepsin K, an osteoclast marker [
ALP and TRAP activity were determined by nitrophenol based method as described by Bessy et al. [
Serum osteocalcin (OC) content was determined using an Osteocalcin EIA kit (Xinyubio-Technology, Inc., China) as described in the manufacturer’s directions. Homocysteine (HCY) was measured by use of an enzymatic fluorescence polarization immunoassay on an Axsym analyzer (Abbott, Wiesbaden, Germany). C-terminal crosslinked telopeptides of collagen type I (CTX) were quantified by ELISA (Sunbio, Inc., China).
The murine mesenchymal stem cell line was purchased from the Beijing Lihao Inc., China, and grown in a DMEM medium supplemented with 10% fetal bovine serum (FBS), penicillin (100 U/mL), and streptomycin (100
In serum, glutathione peroxidase (GPx) activity, glutathione reductase (GR) activity, catalase (CAT) activity, Na+K+ATPase activity, and glutathione S transferase (GST) activity were quantified by ELISA (Sunbio, Inc., China).
Data were expressed as the mean
Ovariectomized (OVX) animal models, in a variety of species, have been used to evaluate the mechanism of or to assess the effect of drugs on osteoporosis. Mechanical strength of bones is the most important parameter related to fracture risk. Therefore, this study first investigated the effect of cordycepin on mechanical strength in OVX osteopenic rats. The average maximum fracture loading to the femoral necks was lower in the OVX group compared with the sham group (Figure
Effects of cordycepin on mechanical strength of the femoral neck. The data are presented as mean ± SD (
Based on the results of mechanical strength, the trabecular number and thickness were studied. In the current study, we found that treatment of osteopenic OVX rats with cordycepin significantly increased maximal load compared to OVX animals. At the end of the 8-week treatment period, osteoblast surface in the lumbar vertebrae was not affected by OVX or any treatment (Figure
Effects of cordycepin on bone ObPm/BPm. Data are expressed as the mean ± SEM (
Estrogen deficiency induces increased body weight in ovariectomized rats. The body weight gain pattern is shown in Figure
Effects of cordycepin on body weight changes for the study (◆sham group, ■OVX group, □cordycepin-5 group, ▲cordycepin-20 group, and ●cordycepin-10 group). Body weights were higher in the ovariectomized (OVX) animals than in sham-operated ones. Cordycepin-20 had similar body weights with the OVX animals in the former 5 weeks. From 5 weeks after the treatment was initiated, cordycepin-20 significantly increased body weights compared to sham group.
Bone histomorphometry was also performed to determine the effects of cordycepin treatment on cancellous bone mass and levels of bone formation and resorption. A sample photomicrograph is presented in Figure
Histology of lumbar vertebrae. The bone structure was photographed under a light microscope. It shows that there was a significant trabecular bone loss in the OVX rat (b), whereas the cordycepin-20 treatment rat section (c) seems near normal compared with sham-operated animals (a).
The current studies demonstrated that systemic treatment with cordycepin has a strong bone anabolic effect in OVX rats. The mechanism of it also needs to be studied in this paper.
ALP is a noncollagenous protein secreted by osteoblast, which is essential for bone mineralization [
Effects of cordycepin on plasma enzymes in ovariectomized rats.
Groups | TRAP level (uM) | ALP level (mM) |
---|---|---|
Sham | 0.22 ± 0.11** | 3.25 ± 0.12** |
OVX | 0.82 ± 0.11 | 7.21 ± 0.10 |
Cordycepin-20 | 0.33 ± 0.02** | 4.11 ± 0.04* |
Cordycepin-10 | 0.61 ± 0.02 | 4.82 ± 0.06* |
Cordycepin-5 | 0.70 ± 0.03 | 7.22 ± 0.01 |
Values are mean ± SEM.
Osteocalcin (OC), homocysteine (HCY), and collagen type I (CTX) are known as serum markers reflecting osteoblast activities including bone formation and turnover [
Effects of cordycepin on plasma proteins.
Groups | Serum OC (ng/mL) | Serum HCY ( |
Serum CTX (ng/mL) |
---|---|---|---|
Sham | 81.0 ± 5.0 | 7.7 ± 1.1 | 75.5 ± 4.2 |
OVX | 61.4 ± 5.1 | 9.2 ± 2.0 | 100.3 ± 5.0 |
Cordycepin-20 | 84.1 ± 5.1** | 8.0 ± 1.0 | 79.0 ± 8.1** |
Cordycepin-10 | 73.6 ± 4.0* | 9.2 ± 3.3 | 85.1 ± 9.0 |
Cordycepin-5 | 70.6 ± 3.2 | 8.0 ± 2.1 | 90.3 ± 4.4 |
Values are mean ± SEM.
Oxidative stress and free radicals have been implicated in the pathogenesis of osteoporosis. Therefore, antioxidant compounds have the potential to be used in the prevention and treatment of the disease. Reduced glutathione (GSH) is one of the primary endogenous antioxidant defense systems, which removes hydrogen peroxide and lipid peroxides. Decline in GSH levels could either increase or reflect oxidative status [
Effect of cordycepin on the activity of various enzymes.
Different groups | GPx | GR | GST | CAT | Na+K+ATPase |
---|---|---|---|---|---|
Sham | 15.98 ± 1.23*** | 35.55 ± 2.51*** | 17.00 ± 1.22** | 7.11 ± 0.33* | 4.52 ± 0.32** |
OVX | 8.01 ± 0.42 | 20.88 ± 2.11 | 10.07 ± 1.11 | 4.22 ± 0.13 | 2.00 ± 0.13 |
Cordycepin-20 | 13.16 ± 1.32** | 29.01 ± 2.21*** | 13.66 ± 0.90* | 5.78 ± 0.20* | 4.11 ± 0.22* |
Cordycepin-10 | 9.10 ± 1.02 | 26.00 ± 2.22 | 13.00 ± 0.91 | 4.70 ± 0.21 | 3.51 ± 0.23 |
Cordycepin-5 | 8.16 ± 1.31 | 21.21 ± 2.20 | 10.10 ± 0.92 | 4.28 ± 0.33* | 2.10 ± 0.11 |
Values are shown as means ± SEM. *
In conclusion, our findings first showed that oral administration of cordycepin can counteract the bone loss in an experimental model of established osteoporosis. These findings suggested that the mechanism of cordycepin is due to decrease ALP activity and TRAP activity both
The authors declare that there is no conflict of interests.
This work was supported by Natural Science Foundation of Shanxi Province of China (2012JQ4020). This work was also supported by grants from the National High Technology Research and Development Program of China (863 Program) (no. 2012AA02A603) and Xijing Hospital Department Support Grant (no. XJZT13Z07).