The Effects of Quassinoid-Rich Eurycoma longifolia Extract on Bone Turnover and Histomorphometry Indices in the Androgen-Deficient Osteoporosis Rat Model

Ginsenoside Rb2 exhibits therapeutic value for male osteoporosis in orchiectomy mice by suppressing osteoclastogenesis and modulating NF-κB/MAPK signaling pathways

Osteoporosis (OP) is a systemic disorder characterized by decreased bone mass as well as deteriorated microarchitecture. Although OP in men is common, it has received much less attention than that in women. Ginseng, a famous traditional herb in Asia, is used to strengthen and repair bones by invigorating vital bioenergy and maintaining body homeostasis in dietary intake and clinical applications. However, there is currently no study investigating the impact of ginseng and its active compounds on male osteoporosis. In this study, RNA sequencing and bioinformatic analysis were conducted to reveal the influence of Ginsenoside-Rb2 on RAW264.7 cells and its underlying signaling pathways. The potential anti-osteoporosis effects of Rb2 as well as its molecular mechanisms were elucidated in RAW264.7 cells and BMMs by TRAP staining, F-actin belt staining, qRT-PCR and WB. Moreover, orchiectomy (ORX) was utilized to demonstrate the influence of Rb2 on bone mass loss in vivo by micro-CT scanning, and H&E, TRAP, and IHC staining. The results suggested that Rb2 suppressed osteoclastogenesis and mitigated bone loss in orchiectomy mice through NF-κB/MAPK signaling pathways. These findings indicate that ginseng as well as its active component Rb2 have potential therapeutic value in the management of osteoporosis in men.

Treatment of osteoporosis using a selective androgen receptor modulator ostarine in an orchiectomized rat model

PURPOSE

The selective androgen receptor modulator ostarine has been shown to have advantageous effects on skeletal tissue properties, reducing muscle wasting and improving physical function in males. However, data on effects in male osteoporosis remain limited. In this study, the effects of ostarine on osteoporotic bone were evaluated in a rat model of male osteoporosis and compared with those of testosterone treatments.

METHODS

Eight-month-old male Sprague-Dawley rats were either non-orchiectomized to serve as a healthy control (Non-Orx, Group 1) or orchiectomized (Orx, Groups 2-6) and then grouped (n = 15/group): (1) Non-Orx, (2) Orx, (3) Ostarine Therapy, (4) Testosterone Therapy, (5) Ostarine Prophylaxis and (6) Testosterone Prophylaxis. Prophylaxis treatments started directly after orchiectomy and continued for 18 weeks, whereas Therapy treatments were initiated 12 weeks after Orx. Ostarine and Testosterone were applied orally at daily doses of 0.4 and 50 mg/kg body weight, respectively. The lumbar vertebral bodies and femora were analyzed using biomechanical, micro-CT, ashing, and gene expression analyses.

RESULTS

Ostarine Prophylaxis showed positive effects in preventing osteoporotic changes in cortical and trabecular bone (femoral trabecular density: 26.01 ± 9.1% vs. 20.75 ± 1.2% in Orx and in L4: 16.3 ± 7.3% vs 11.8 ± 2.9% in Orx); biomechanical parameters were not affected; prostate weight was increased (0.62 ± 0.13 g vs 0.18 ± 0.07 g in Orx). Ostarine Therapy increased solely the cortical density of the femur (1.25 ± 0.03 g/cm3 vs. 1.18 ± 0.04 g/cm3 in Orx); other bone parameters remained unaffected. Testosteron Prophylaxis positively influenced cortical density in femur (1.24 ± 0.05 g/cm3 vs. 1.18 ± 0.04 g/cm3 in Orx); Test. Therapy did not change any bony parameters.

CONCLUSION

Ostarine Prophylaxis could be further investigated as a preventative treatment for male osteoporosis, but an androgenic effect on the prostate should be taken into consideration, and combination therapies with other anti-osteoporosis agents could be considered.

The roles of sclerostin and irisin on bone and muscle of orchiectomized rats

BACKGROUND

The reduction in androgen level gives rise to a decrease in bone mineral density (BMD) and muscle strength, but the exact mechanisms are unclear. We investigated the roles of novel cytokines of sclerostin and irisin on bone and muscle of orchiectomized rats.

METHODS

Twenty 3-month-old male rats were randomized to receive sham or orchiectomy (ORX) operation. Rats were euthanized after 8 weeks of surgery, and serum levels of sclerostin and irisin were measured by enzyme-linked immunosorbent assay at baseline and execution. Grip strength was measured by a grip strength tester at baseline and before execution. BMD and bone microarchitecture were measured by microcomputed tomography. The samples of bone and muscle were harvested at execution. Bone biomechanics were measured by three-point bending tests and vertebral body indentation tests. Bone and muscle histological features were analyzed by hematoxylin and eosin stain, Von Kossa's stain and tartrate resistant acid phosphatase stain. Simple linear regression analyses were used to analyze the relationships between serum levels of sclerostin, irisin and grip strength and BMD of ORX rats.

RESULTS

Serum sclerostin level increased from 279 ± 44 pg/mL to 586 ± 57 pg/mL since baseline to 8 weeks after ORX (P = 0.002), which was significantly higher than that in sham rats (406 ± 20 pg/mL at execution) (P = 0.012). Serum irisin level decreased from 4.12 ± 0.20 ng/mL to 3.55 ± 0.29 ng/mL since baseline to 8 weeks of ORX (P = 0.048), which was significantly lower than sham rats (4.84 ± 0.37 pg/mL at execution) (P = 0.013). Trabecular BMD, parameters of bone microarchitecture, bone strength, grip strength and the myofibers size of soleus muscles were significantly lower in ORX rats than in sham group. Grip strength was positively correlated with femoral trabecular BMD (r = 0.713, P < 0.001) and bone volume/total volume (r = 0.712, P < 0.001) in all rats. The serum sclerostin level was negatively correlated to femoral trabecular BMD (r = -0.508, P = 0.022) and grip strength (r = -0.492, P = 0.028). Serum irisin level was positively correlated with femoral trabecular BMD (r = 0.597, P = 0.005), but no obvious correlation was found between irisin level and muscle strength in all rats.

CONCLUSIONS

Reduced BMD, impaired bone microarchitecture, weak strength of bone and muscle, and thin myofibers were induced by androgen deficiency of ORX rats. Serum sclerostin and irisin levels were significantly changed after ORX, which might be closely correlated with the occurrence of osteoporosis and sarcopenia in ORX rats.

Quassinoids from Eurycoma longifolia and their bone formation evaluation in zebrafish, C3H10 cells and silico

Phytochemicals with bone formation potential in traditional medicines captured more and more attentions due to their advantages to bone loss and fewer side effects. As a famous aphrodisiac phytomedicine, Eurycoma longifolia (EL) has acquired general recognition in improving male sexual health, and thus been considered as traditional medicine for the treatment of androgen-deficient osteoporosis. Although the aqueous extract of EL had been proved to be beneficial to bone loss, the active constituents and the mechanisms underlying the effects are still obscure. The current study performed a chemical investigation on the roots of EL, which resulted in the isolation and identification of ten quassinoids (EL-1-EL-10), and then conducted their osteogenic activity evaluations in vivo zebrafish model with or without dexamethasone (Dex) and in vitro C3H10 cell model. The result displayed that most tested concentrations of EL-1-EL-5 could significantly increase the mineralization areas and integrated optical densities (IODs) of skull in both zebrafish model. The majority tested concentrations of EL-1-EL-5 could also improve the mRNA expression of early osteogenic associated genes ALPL, Runx2a, Sp7 in zebrafish model without Dex, but only a few could accelerate the mRNA expression of late osteogenic associated genes OCN. These results suggested the ability of EL-1-EL-5 to increase bone formation mainly by accelerating osteogenic differentiation at the early stage. The structure-based virtual screening based on the pharmacophores in ePharmaLib, as well as the molecular docking study, implied that the effects of the quassinoids (EL-1-EL-5) on the enhancement of bone formation might be related with improving the content and the activity of androgen through binding with CYP19A, SHBG and AKR1C2, and activating bone metabolism-related ANDR target genes and signal pathways by combining with ANDR directly. Although the assumptions are in silico model-based and further in vitro and in vivo validations are still necessary, we provided a new perspective to explore the potential of EL to be used as an alternative treatment for not only androgen-deficient osteoporosis, but also estrogen-deficient bone loss, by combining with SHBG.

Differentially expressed genes on the growth of mouse Leydig cells treated with standardised Eurycoma longifolia extract

Eurycoma (E.) longifolia Jack (Tongkat Ali) is a widely applied medicine that has been reported to boost serum testosterone and increase muscle mass. However, its actual biological targets and effects on an in vitro level remain poorly understood. Therefore, the present study aimed to investigate the effects of a standardised E. longifolia extract (F2) on the growth and its associated gene expression profile in mouse Leydig cells. F2, even at lower doses, was found to induce a high level of testosterone by ELISA. The level was as high as the levels induced by eurycomanone and formestane in Leydig cells. However, Leydig cells treated with F2 demonstrated reduced viability, which was likely due to the diminished cell population at the G0/G1 phase and increased cell population arrested at the S phase in the cell cycle, as assessed by MTT assay and flow cytometry, respectively. Cell viability was revived when the treatment time‑point was prolonged to 96 h. Genome‑wide gene analysis by reverse transcription‑quantitative PCR of F2‑treated Leydig cells at 72 h, when the cell growth was not revived, and 96 h, when the cell growth had started to revive, revealed cyclin‑dependent kinase‑like 2 (CDKL2) to be a potential target in regulating the viability of F2‑treated Leydig cells. Functional analysis, as analysed using GeneMANIA Cytoscape program v.3.6.0 (https://genemania.org/), further suggested that CDKL2 could act in concert with Casitas B‑lineage lymphoma and sphingosine kinase 1 interactor‑A‑kinase anchoring protein domain‑containing genes to regulate the viability of F2‑treated Leydig cells. The findings of the present study provide new insights regarding the potential molecular targets associated with the biological effect of E. longifolia extract on cell growth, particularly on the cell cycle, which could aid in enhancing the bioefficacy and reducing the toxicity of this natural product in the future.

Quercetin as an Agent for Protecting the Bone: A Review of the Current Evidence

Quercetin is a flavonoid abundantly found in fruits and vegetables. It possesses a wide spectrum of biological activities, thus suggesting a role in disease prevention and health promotion. The present review aimed to uncover the bone-sparing effects of quercetin and its mechanism of action. Animal studies have found that the action of quercetin on bone is largely protective, with a small number of studies reporting negative outcomes. Quercetin was shown to inhibit RANKL-mediated osteoclastogenesis, osteoblast apoptosis, oxidative stress and inflammatory response while promoting osteogenesis, angiogenesis, antioxidant expression, adipocyte apoptosis and osteoclast apoptosis. The possible underlying mechanisms involved are regulation of Wnt, NF-κB, Nrf2, SMAD-dependent, and intrinsic and extrinsic apoptotic pathways. On the other hand, quercetin was shown to exert complex and competing actions on the MAPK signalling pathway to orchestrate bone metabolism, resulting in both stimulatory and inhibitory effects on bone in parallel. The overall interaction is believed to result in a positive effect on bone. Considering the important contributions of quercetin in regulating bone homeostasis, it may be considered an economical and promising agent for improving bone health. The documented preclinical findings await further validation from human clinical trials.

Plants in the management of male infertility

This review attempts to collate existing data and provide the perspectives for future studies on the effects of plants on the male gonads. For many of these medicinal plants such as Lepidium meyenii, Rupus coreanus, Tribulus terrestres, Panax ginseng, Petasites japonicas, Apium graveolens, Eurycoma longifólia, Pedalium murex, Corchorus depressus, Mucuna pruriens, Astragalus membranaceus, Nigella sativa, Crataegus monogyna, Fagara tessmannii, Phaleria macrocarpa, Anacyclus pyrethrum, Cynomorium songaricum and Morinda officinalis, the mechanism of actions of their active principles and crude extracts has been shown in both laboratory animals, in vitro, and human studies, and includes their antioxidant, anti-inflammatory, spermatogenesis-inducing, aphrodisiac, smooth muscle relaxing and androgenic properties. Several active chemical leads including glucosinolates, anthocyanins, protodioscin, ginsenosides, sesquiterpenes, phyto-oestrogens, quassinoids, diosgenin, thymoquinone, proanthocyanidins and bajijiasu isolated from these plants are known to have target effects on the testis, but efforts have been limited in their application at the clinical level. There still appear to be many more extracts of medicinal plants that have not been characterised to determine the phytochemicals unique to them that have target effects on the gonads. Further, collaborative efforts at isolating pro-drug candidates from medicinal plants for studies at the molecular, cellular and clinical level towards elucidating their mechanisms of action on the testes are therefore warranted in the light of the current male fertility crisis.

Anthocyanin-rich extract from black rice (Oryza sativa L. Japonica) ameliorates diabetic osteoporosis in rats

Diabetic osteoporosis (DOP) is a systemic endocrine-metabolic osteopathy which has the characteristics of bone mineral density (BMD) reduction and bone microstructural destruction. Although anthocyanin-rich extract from black rice (AEBR) was reported to have a beneficial effect on diabetic rats, no studies have been performed on whether black rice anthocyanins are beneficial for diabetic osteoporosis. Therefore, in this study, a streptozotocin-induced diabetic rat model was established to investigate the protective effect of AEBR on diabetes-induced osteoporosis and its possible mechanism. AEBR at three doses (0.5, 1.0, and 2.0 g kg^-1 d^-1) were administered by oral gavage to diabetic rats for 8 weeks. The blood glucose, BMD, bone histomorphometry parameters, serum bone turnover biomarkers, bone marrow adipocyte numbers, as well as osteoprotegerin (OPG), runt-related transcription factor 2 (RUNX 2), and receptor activator of nuclear factor-κ B ligand (RANKL) protein expression in bone and serum were detected. The results indicated that AEBR dose-dependently decreased the blood glucose, increased the BMD, and decreased the serum bone turnover markers. The bone microstructure and osteoclast numbers in bone tissues returned to normal in the high AEBR dosage group; at the same time, the AEBR dose-dependently suppressed bone marrow adipogenesis. The RUNX 2 as well as the OPG/RANKL ratio in diabetic rats' bone tissues increased significantly in the AEBR treatment group. Our results indicate that AEBR administration can ameliorate bone loss caused by diabetes; this is mainly attributed to its inhibition of bone turnover, suppression of bone marrow adipogenesis, and up-regulation of RUNX 2 and the OPG/RANKL expression ratio.

Biomechanical and tomographic differences in the microarchitecture and strength of trabecular and cortical bone in the early stage of male osteoporosis

Osteoporosis is a continuous process of loss of bone tissue. Compared to women, osteoporosis in men is associated with greater morbidity and mortality. In this study, we conducted tomographic and biomechanical evaluations of trabecular and cortical bone in the early stage of male osteoporosis. Male Wistar rats were subjected to orchiectomy and sham operation. Four weeks after being castrated, decreased levels of testosterone in plasma were found and resulted in concurrent bone loss. Separately, the orchiectomy led to significant tomographic alterations in the trabecular bone number, trabecular separation, and trabecular pattern factor. Data of a mechanistic compression test further showed that the orchiectomy diminished the maximum loading force, displacement at maximum load, energy at maximum load, and ultimate stress. Interestingly, orchiectomy-triggered changes in the maximum loading force and tomographic parameters were highly correlated. In contrast, tomographic and biomechanical analyses showed that 4 weeks after rats were orchiectomized, the thickness, area, maximum loading force, bone stiffness, energy at maximum load, and ultimate stress of the cortical bone were not changed. Taken together, this study showed specific differences in the microarchitecture and strength of trabecular bone in the early stage of male osteoporosis.

Brain Cortical and Hippocampal Dopamine: A New Mechanistic Approach for Eurycoma longifolia Well-Known Aphrodisiac Activity and Its Chemical Characterization

Eurycoma longifolia Jack (Fam.: Simaroubaceae), known as Tongkat Ali (TA), has been known as a symbol of virility and sexual power for men. Metabolic profiling of the aqueous extract of E. longifolia (AEEL) using UPLC-MS/MS in both positive and negative modes allowed the identification of seventeen metabolites. The identified compounds were classified into four groups: quassinoids, alkaloids, triterpenes, and biphenylneolignans. AEEL is considered safe with oral LD₅₀ cut-off >5000 mg/kg. Oral administration of 50, 100, 200, 400, or 800 mg/kg of AEEL for 10 consecutive days to Sprague-Dawley male rats caused significant reductions in mounting, intromission, and ejaculation latencies and increased penile erection index. AEEL increased total body weight and relative weights of seminal vesicles and prostate. Total and free serum testosterone and brain cortical and hippocampal dopamine content was significantly elevated in treated groups with no significant effects on serotonin or noradrenaline content.

Icariin Prevents Diabetes-Induced Bone Loss in Rats by Reducing Blood Glucose and Suppressing Bone Turnover

Diabetic Osteoporosis (DOP) is a common metabolic bone disease, characterized by decreased bone mineral density (BMD) and destruction of bone microstructure. It has been reported that icariin is beneficial for estrogen deficiency-induced osteoporosis, and alcohol-induced osteoporosis; whether icariin has protective effects on diabetes-induced osteoporosis has not been reported. In this study, a rat model of diabetic osteoporosis was established by streptozotocin injection, the bone protective effects and potential mechanism of icariin on diabetes-induced bone loss was observed. Thirty 8-week-old female Sprague Dawley rats were divided into control group (vehicle treatment), T1DM (diabetic) group and T1DM-icariin (ICA) group (diabetic rats treated with icariin), 10 rats in each group. The bone histomorphometry parameters, bone mineral density (BMD), serum bone turnover markers, and bone marrow adipogenesis were analyzed after 8 weeks of icariin administration. The results showed consumption of icariin at a doses of 100 mg kg⁻¹ decreased blood glucose, and increased the BMD of diabetic rats. Icariin effectively decreased serum bone turnover marker levels, including CTX-1, ALP, TRACP 5b, osteocalcin, and PINP. Meanwhile, the bone histomorphometry parameters, the number of osteoclasts per bone perimeter were turned to be normal level, and the icariin treatment suppressed bone marrow adipogenesis. The runt-related transcription factor 2 (RUNX 2), as well as the osteoprotegerin (OPG)/receptor activator of nuclear factor-κ B ligand (RANKL) ratio in serum and bone tissues were increased significantly after icariin treatment in diabetic rats. All of the above indicate that oral administration of icariin can prevent diabetic osteoporosis; the effect is mainly related to its ability to reduce blood glucose, inhibit bone turnover and bone marrow adipogenesis, as well as up-regulate bone RUNX 2, and OPG expression.