Isoflavones improve collagen I and glycosaminoglycans and prevent bone loss in type 1 diabetic rats

Antiosteoporosis effect of bryodulcosigenin on ovariectomy-induced osteoporosis in experimental rats

PURPOSE

Osteoporosis is a bone disease which commonly occurred in postmenopausal women. Almost 10 percent of world population and approximately 30% of women (postmenopausal) suffer from this disease. Alternative medicine has great success in the treatment of osteoporosis disease. Bryodulcosigenin, a potent phytoconstituent, already displayed the anti-inflammatory and antioxidant effect. In this study, we made effort to analyze the antiosteoporosis effect of bryodulcosigenin against ovariectomy (OVX) induced osteoporosis in rats.

METHODS

Swiss albino Wistar rats were grouped into fIve groups and given an oral dose of bryodulcosigenin (10, 20 and 30 mg/kg) for eight weeks. Body weight, uterus, bone mineral density, cytokines, hormones parameters, transforming growth factor (TGF)-β, insulin-like growth factor (IGF), osteoprotegerin (OPG), receptor activator of nuclear factor kappa-Β ligand (RANKL), and its ratio were estimated.

RESULTS

Bryodulcosigenin significantly (p < 0.001) suppressed the body weight and enhanced the uterine weight and significantly (p < 0.001) increased the bone mineral density in whole femur, caput femoris, distal femur and proximal femur. Bryodulcosigenin significantly (P < 0.001) altered the level of biochemical parameters at dose dependent manner, significantly (P < 0.001) improved the level of estrogen and suppressed the level of follicle stimulating hormone and luteinizing hormone. Bryodulcosigenin significantly (P < 0.001) improved the level of OPG and suppressed the level of RANKL.

CONCLUSIONS

Bryodulcosigenin reduced the cytokines level and suppressed the TGF-β and IGF. We concluded that bryodulcosigenin is an antiosteoporosis medication based on the findings.

Sambucus williamsii Hance maintains bone homeostasis in hyperglycemia-induced osteopenia by reversing oxidative stress via cGMP/PKG signal transduction

BACKGROUND

Sambucus williamsii Hance (SWH) has effectively been adopted to treat joint and bone disorders. Diabetes-induced osteopenia (DOP) is caused primarily by impaired bone formation as a result of hyperglycemia. We had previously demonstrated that SWH extract accelerated fracture healing and promoted osteoblastic MC3T3-E1 cell proliferation and osteogenic differentiation. This study assessed the impacts of SWH extract on diabetes-induced bone loss and explored the mechanisms underlying its osteoprotective effects.

METHODS

This work employed MC3T3-E1 cell line for evaluating how SWH extract affected osteogenesis, oxidative stress (OS), and the underlying mechanism in vitro. Streptozotocin-induced osteopenia mouse model was applied with the purpose of assessing SWH extract's osteoprotection on bone homeostasis in vivo.

RESULTS

The increased OS of MC3T3-E1 cells exposed to high glucose (HG) was largely because of the upregulation of pro-oxidant genes and the downregulation of antioxidant genes, whereas SWH extract reduced the OS by modulating NADPH oxidase-4 and thioredoxin-related genes by activating cyclic guanosine monophosphate (cGMP) production and increasing the level of cGMP-mediated protein kinase G type-2 (PKG2). The oral administration of SWH extract maintained bone homeostasis in type 1 diabetes mellitus (T1DM) mice by enhancing osteogenesis while decreasing OS. In bones from hyperglycemia-induced osteopenia mice and HG-treated MC3T3-E1 cells, the SWH extract achieved the osteoprotective effects through activating the cGMP/PKG2 signaling pathway, upregulating the level of antioxidant genes, as well as downregulating the level of pro-oxidant genes.

CONCLUSION

SWH extract exerts osteoprotective effects on hyperglycemia-induced osteopenia by reversing OS via cGMP/PKG signal transduction and is a potential therapy for DOP.

Isoflavone Protects the Renal Tissue of Diabetic Ovariectomized Rats via PPARγ

Diabetes associated with post-menopause is related to a worse condition of kidney disease. Taking into consideration that this disorder may be regulated by estrogenic mediators, we evaluated the renal protective effect of isoflavone. We investigated the role of the PPARγ in the pathogenesis of the disease. For this study, we used diabetic female rats in a postmenopausal model through ovariectomy. The animals were treated with isoflavone or 17β-estradiol. A dosage was administered to bring on blood glycemia, and through immunohistochemistry, we evaluated the immunoreactivity of PPARγ in the endometrium and renal tissue. We analyzed the immunoreactivity of renal injury molecule KIM-1 and the collagen and glycogen densities in the kidney. Through bioinformatics analysis, we observed PPARγ and COL1A1 gene expression under the influence of different glucose doses. In particular, we observed that isoflavone and 17β-estradiol regulate blood glycemia. Renal injury was inhibited by isoflavone, observed by a reduction in KIM-1, along with glycogen accumulation. These benefits of isoflavone may be associated with PPARγ overexpression in the kidneys and endometrium of diabetic ovariectomized rats.

PERK activator CCT020312 prevents inflammation-mediated osteoporosis in the ovariectomized rats

OBJECTIVE

To investigate the therapeutic effects of PERK activator CCT020312 (CCT) on inflammation-mediated osteoporosis (IMO) in ovariectomized rats.

METHODS

Rats were divided into Sham, IMO, IMO + 1 mg/kg CCT and IMO + 2 mg/kg CCT groups. IMO models were constructed by bilateral ovariectomy (OVX) on 1st day followed by injection with magnesium silicate (Talc) on the 59th day. Sham rats did not undergo OVX surgery and were injected with saline instead of Talc. From 60th to 79th day, rats were treated with DMSO (vehicle control) in the Sham and IMO groups, and 1 or 2 mg/kg CCT020312 in treatment groups. Osteopontin (OPN), osteocalcin (OCN), tartrate-resistant acid phosphatase (TRAP), C-terminal telopeptide of type I collagen (CTX-I), and pro-inflammatory factors were measured on the 80th day. ProdigyDEXA was used to evaluate bone mineral density and content (BMD/BMC). Bone volume/total volume (BV/TV), connectivity density (Conn.D), trabecular number (Tb.N), and trabecular separation (Tb.Sp) was assessed using 3D micro-CT scanner.

RESULTS

CCT up-regulated Conn.D, BV/TV, and Tb.N, but down-regulated Tb.Sp in IMO rats. Besides, the declined femoral BMD and BMC in IMO rats were elevated after CCT treatment. Besides, IMO rats represented declined OPN and OCN, as well as increased TRAP, CTX-I, and pro-inflammatory factors, whereas those in the treatment groups were ameliorated regarding these indexes, with 2 mg/kg CCT showing better effect.

CONCLUSION

PERK activator CCT020312 can be served as a new therapeutic option for the protection against bone loss in the OVX rat model associated with inflammation probably by manipulating inflammatory factors.