Rapid onset of bone loss is a frequent complication of systemic glucocorticoid therapy which may lead to fragility fractures. Glucocorticoid action in bone depends upon the activity of 11β-hydroxysteroid dehydrogenase type 1 enzyme (11β-HSD1). Regulations of 11β-HSD1 activity may protect the bone against bone loss due to excess glucocorticoids. Glycyrrhizic acid (GCA) is a potent inhibitor of 11β-HSD. Treatment with GCA led to significant reduction in bone resorption markers. In this study we determined the effect of GCA on 11β-HSD1 activity in bones of glucocorticoid-induced osteoporotic rats. Thirty-six male Sprague-Dawley rats (aged 3 months and weighing 250-300 g) were divided randomly into groups of ten. (1) G1, sham operated group; (2) G2, adrenalectomized rats administered with intramuscular dexamethasone 120 μg/kg/day and oral vehicle normal saline vehicle; and (3) G3, adrenalectomized rats administered with intramuscular dexamethasone 120 μg/kg/day and oral GCA 120 mg/kg/day The results showed that GCA reduced plasma corticosterone concentration. GCA also reduced serum concentration of the bone resorption marker, pyridinoline and induced 11β-HSD1 dehydrogenase activity in the bone. GCA improved bone structure, which contributed to stronger bone. Therefore, GCA has the potential to be used as an agent to protect the bone against glucocorticoid induced osteoporosis.
Glucocorticoid-induced osteoporosis is one of the common causes of secondary osteoporosis. Piper sarmentosum (Ps) extract possesses antioxidant and anti-inflammatory activities. In this study, we determined the correlation between the effects of Ps leaf water extract with the regulation of 11β-hydroxysteroid dehydrogenase (HSD) type 1 enzyme activity in serum and bone of glucocorticoid-induced osteoporotic rats. Twenty-four Sprague-Dawley rats were grouped into following: G1: sham-operated group administered with intramuscular vehicle olive oil and vehicle normal saline orally; G2: adrenalectomized (adrx) control group given intramuscular dexamethasone (120 μg/kg/day) and vehicle normal saline orally; G3: adrx group given intramuscular dexamethasone (120 μg/kg/day) and water extract of Piper sarmentosum (125 mg/kg/day) orally. After two months, the femur and serum were taken for ELISA analysis. Results showed that Ps leaf water extract significantly reduced the femur corticosterone concentration (p < 0.05). This suggests that Ps leaf water extract was able to prevent bone loss due to long-term glucocorticoid therapy by acting locally on the bone cells by increasing the dehydrogenase action of 11β-HSD type 1. Thus, Ps may have the potential to be used as an alternative medicine against osteoporosis and osteoporotic fracture in patients on long-term glucocorticoid treatment.
Glucocorticoids are one of the causes of secondary osteoporosis. The aqueous extract of Piper sarmentosum contains flavonoids that possess antioxidant effects. In this study, we determined the effects of aqueous Piper sarmentosum leaf extract on structural, dynamic and static histomorphometric changes from osteoporotic bones of rats induced with glucocorticoids. Thirty-two Sprague-Dawley rats were divided equally into four groups-Sham control group given vehicles (intramuscular (IM) olive oil and oral normal saline); AC: Adrenalectomised (Adrx) control group given IM dexamethasone (DEX) (120 μg/kg/day) and vehicle (oral normal saline); AP: Adrx group administered IM DEX (120 μg/kg/day) and aqueous Piper sarmentosum leaf extract (125 mg/kg/day) orally; and AG: Adrx group administered IM DEX (120 μg/kg/day) and oral glycyrrhizic acid (GCA) (120 mg/kg/day). Histomorphometric measurements showed that the bone volume, trabecular thickness, trabecular number, osteoid and osteoblast surfaces, double-labelled trabecular surface, mineralizing surface and bone formation rate of rats given aqueous Piper sarmentosum leaf extract were significantly increased (p < 0.05), whereas the trabecular separation and osteoclast surface were significantly reduced (p < 0.05). This study suggests that aqueous Piper sarmentosum leaf extract was able to prevent bone loss in prolonged glucocorticoid therapy. Thus, Piper sarmentosum has the potential to be used as an alternative medicine against osteoporosis and osteoporotic fractures in patients undergoing long-term glucocorticoid therapy.