Effects Of Crocus Sativus Extract On Treatment Of Osteoporosis In Ovariectomized Rats

Osteoporosis is a kind of systematic skeleton disease in which bone mass is reduced, the microstructure of bone is degenerated, bone strength is weakened, and accordingly bone is fragile and more likely to break. Osteoporosis has been a social and economic problem for all of the world because of its high morbidity, enormous distribution and large resource consumption. What is more, women are more susceptible to Osteoporosis than men for the reason of lower peak bone mass and decreasing estrogen level after menopause. This kind of Osteoporosis is usually called Postmenopausal Osteoporosis (PMO for short), which is the main type of primary cultured Osteoporosis. As a common but serious complication of Osteoporosis, Osteoporotic fracture can have badly impact on the victims'quality of lives. As far as preventive and therapeutic drugs for Osteoporosis are concerned, there are mainly two groups: one is bone absorption-inhibitor such as estrogen, calcium, vitamin D, calcitonin, diphosphonate and so on, the other is bone formation-acceleration such as fluoride, strontium and so on. Both groups of drugs belong to replacement therapy which has more or less problems if we take into account of their economy, safety and compliance of patients. The Chinese traditional herb medicine has been paid more and more attention to by researchers for its comprehensive management, little cytotoxic side effects and reasonable price. Modern pharmacological studies indicate that Crocus sativus has potential anti - osteoporosis effects. As regards our country, therefore, health-related departments always emphasize the importance of taking advantage of Chinese herb medicine and developing anti-osteoporosis drugs with independent intellectual properties. It is just in this sense that our study begins.Objective: To study the effects of Crocus sativus extract on bone mineral density (BMD), biomechanical property, bone metabolism biochemical markers, microscopic structure of bone trabecula and bone histomorphometry in ovariectomized rats, and to explore the therapeutic effects of Osteoporosis caused by the deficiency of estrogen.Methods: Forty-eight female Sprague-Dawley rats, four months old, were divided randomly into six groups: the sham-operating group (Sham) , the ovarictomized group (OVX) , estradiol valerate treated group (E2), low-dose of Crocus sativus treated group (L-Crocus), medium-dose of Crocus sativus treated group (M-Crocus) and high-dose of Crocus sativus treated group (H-Crocus). We established the animal model of OVX through the method of removing both ovaries of rats. All the rats were ovarictomized except Sham group, in which the rats were only removed some adipose tissue near ovary. Four weeks later, Sham group and OVX group were intra-gastric administrated with distilled water, whereas the E2 group received estradiol valerate (0.8mg/kg.d) and other three groups received different dosage of Crocus sativus extract (25, 50, 100mg/kg.d) by gavage respectively for 8 weeks. During the period every rat should be weighed weekly for precise adjustments in feed allocation to be made. Then all the rats were executed and their both femoral bones, vertebra bones and blood sera were harvested. The BMD, biomechanical property, bone metabolism biochemical markers, microscopic structure of bone trabecula, bone histomorphometry, index of uterus and serum estrogen levels were measured respectively. Then, all the collected datum were analyzed by the software SPSS.Results: The BMD, bone strength and serum estradiol levels in three Crocus sativus extract treated groups were significantly higher than that in OVX group (p<0.01), and the serum alkaline phosphatase (ALP) level in the former were obviously lower than that in the latter (p<0.01). Compared with the OVX group, the microscopic structure of bone trabecula and bone histomorphometry were significantly improved (p<0.01). Compared with the E2 group, the index of uterus decreased significantly in three Crocus sativus extract treated groups (p<0.01).Conclusion: Crocus sativus showed the potential effects of treatment of osteoporosis in ovariectomized rats through inhibiting the bone mineral loss, increasing bone strength, reducing bone turnover, improving the microscopic structure of bone trabecula and the bone metabolism. The mechanism of action which needs further study may include antioxidatio, anti-bloodfat, anti-coagulation and estrogen-like component.