Curcumin Activates Sirt3 To Protect Bone Structure In Diabetic Mice

New investigation shows really curcumin’s molecular powerfulness protects bony cells from high-glucose stress, repairs mitochondria, and boosts antioxidant defences, offering dream for tackling diabetes-related bony loss.

Study: Curcumin preserves bony wellness compromised by glucosuria by inhibiting osteoporosis done regularisation of nan SIRT3/FoxO3a signalling pathway. Image Credit: Anicka S / Shutterstock

In a caller study published successful nan journal Scientific Reports, researchers tested whether curcumin counteracts diabetic osteoporosis by activating Sirtuin-3 (SIRT3)/Forkhead container macromolecule O3a (FoxO3a) signaling and nan downstream antioxidant macromolecule web including atomic facet erythroid 2-related facet 2 (NRF2) and its target NAD(P)H:quinone oxidoreductase 1 (NQO1) to curb mitochondrial oxidative accent and reconstruct osteoblast differentiation successful vitro, pinch corresponding gains successful bony microarchitecture successful vivo.

Background

One successful 2 older adults will woody pinch vulnerable bones, and galore besides unrecorded pinch type 2 glucosuria mellitus (T2DM), which is simply a reliable operation that raises fracture consequence and slows healing. Diabetic osteoporosis is driven by chronic hyperglycemia, precocious reactive oxygen type (ROS), and sluggish osteoblast activity, starring to falls, infirmary stays, and rising costs.

Standard osteoporosis narcotics often underperform successful T2DM, and fewer treatments straight hole nan mitochondrial dysfunction that fuels ROS harm successful bony cells. Nutritional polyphenols for illustration curcumin are wide utilized and mostly safe, but their bone-specific actions nether hyperglycemia are not afloat mapped. More investigation is needed to pinpoint mitochondrial targets, corroborate protective pathways, and fine-tune dosing for real-world benefit.

The authors besides statement that curcumin’s system whitethorn nexus mitochondrial regularisation to epigenetic power of osteogenic genes, adding different imaginable therapeutic layer.

About nan study

Mouse osteoblasts (MC3T3-E1 compartment line) were cultured successful Minimum Essential Medium alpha (α-MEM) pinch 10% fetal bovine serum (FBS) astatine 37 °C nether 5% c dioxide (CO₂). To simulate T2DM, cells were exposed to precocious glucose (25.5 mM) for 24 h, past treated pinch curcumin (0, 1, 10, 100 μM) for 48 h. The mediate attraction (10 μM) showed nan strongest protective effect, whereas 1 μM and 100 μM were little effective, suggesting a bell-shaped dose–response pattern.

Cell viability was measured utilizing Cell Counting Kit-8 (CCK-8).

Mitochondrial ultrastructure was assessed by transmission particle microscopy (TEM), and mitochondrial membrane imaginable by 5,5′,6,6′-tetrachloro-1,1′,3,3′-tetraethylbenzimidazolylcarbocyanine iodide (JC-1) travel cytometry. Intracellular ROS were quantified pinch 2′,7′-dichlorofluorescin diacetate (DCFH-DA). Malondialdehyde (MDA), superoxide dismutase 2 (SOD2), and glutathione (GSH) were wished utilizing commercialized kits.

Protein analyses (SIRT3, FoxO3a, NRF2, and NQO1), atomic facet erythroid 2-related facet 2 (NRF2), NADPH oxidase 2 (NOX2) were performed by occidental blotting aft lysis pinch radioimmunoprecipitation assay (RIPA) buffer, quantification by bicinchoninic acerb (BCA) assay, separation via sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), and transportation to polyvinylidene difluoride (PVDF) membranes; blocking and Tris-buffered saline pinch Tween (TBST) procedures followed modular practice.

Stable SIRT3 knockdown was generated by lentiviral short hairpin RNA (shRNA) and verified by occidental blot. Osteogenic differentiation was evaluated by alkaline phosphatase (ALP) and Alizarin Red S staining. In vivo, antheral Sprague-Dawley rats received a high-fat/glucose diet, streptozotocin (STZ; 30 mg/kg), and intraperitoneal curcumin (10 aliases 50 mg/kg); bony microarchitecture was assessed by micro-computed tomography (μCT) and histology.

Study results

High glucose trim MC3T3-E1 viability, curcumin astatine 10 μM brought endurance backmost toward normal; 1 μM and 100 μM had constricted effect, truthful 10 μM was utilized for follow-ups. Apoptosis tracked pinch these changes: cleaved caspase-3 roseate and B-cell lymphoma 2 (Bcl-2) fell nether precocious glucose, and curcumin flipped some signals successful a protective direction.

Electron microscopy showed swollen, cristae-disrupted mitochondria aft precocious glucose, while curcumin curen preserved a much normal morphology. JC-1 information echoed these findings: mitochondrial membrane imaginable dropped pinch precocious glucose but partially recovered aft curcumin exposure.

Redox equilibrium besides improved. High glucose pushed ROS and MDA up and depressed endogenous defenses. Curcumin lowered ROS, reduced MDA, and boosted SOD2 and GSH toward power levels, grounds of a healthier oxidative state. At nan signaling level, precocious glucose suppressed SIRT3, FoxO3a, NRF2, and NQO1, and NOX2; curcumin restored these proteins toward baseline, accordant pinch re-engaging mitochondrial deacetylation and antioxidant programs.

Knocking down SIRT3 removed nan benefit. With SIRT3 silenced, curcumin nary longer helped: viability fell, mitochondrial membrane imaginable dropped, and FoxO3a, NRF2, and NQO1 decreased compared pinch nan high-glucose positive curcumin condition. This nonaccomplishment of protection identifies SIRT3 arsenic nan upstream driver connecting curcumin to antioxidant and cytoprotective effects.

Functionally, osteogenic differentiation followed suit. High glucose blunted maturation, but curcumin restored ALP staining, accrued Alizarin Red S-positive nodules, and raised osteoprotegerin (OPG) and osteocalcin (OCN). Each summation was dampened by SIRT3 knockdown, tying nan rescue to nan SIRT3/FoxO3a axis and its downstream antioxidant signaling alternatively than nonspecific effects. In short, curcumin stabilized mitochondria, improved redox tone, reduced apoptosis, and allowed osteoblasts to proceed toward mineralization contempt hyperglycemia.

The animal information matched nan compartment work. The STZ-plus-diet regimen produced hyperglycemia and humble weight loss, confirming a T2DM-like state. Untreated diabetic rats showed sparse, bladed trabeculae and degraded architecture. Curcumin (10 aliases 50 mg/kg) improved μCT metrics, pinch denser trabecular networks and higher evident bony density; HE sections looked healthier.

Immunohistochemistry showed higher SIRT3 and NRF2 successful bony aft curcumin, accordant pinch mitochondrial and antioxidant reactivation successful vivo. These increases were dose-dependent, pinch higher curcumin producing greater macromolecule look changes. In a mounting wherever modular therapies often lag, these cellular wins translated into tissue-level gains.

Conclusions

Curcumin protected osteoblasts and bony successful diabetic-osteoporosis models by easing mitochondrial oxidative stress, preserving membrane potential, and promoting osteogenic differentiation. The effect required SIRT3 activation and FoxO3a signaling, coincided pinch stronger NRF2-dependent defenses (including NQO1), and vanished pinch SIRT3 silencing.

In rats pinch a T2DM-like condition, curcumin improved trabecular microarchitecture connected μCT and raised bony density indicators successful parallel pinch accrued SIRT3 and NRF2 look successful bony tissue.

These results item nan SIRT3/FoxO3a axis arsenic a therapeutic target, underscore its coordination pinch NRF2-driven antioxidant responses, and support curcumin arsenic a practical, low-cost adjunct for diabetes-related bony fragility, meriting translational studies to refine dose, schedule, and semipermanent information successful humans.

The authors besides position curcumin alongside different earthy compounds for illustration melatonin, groundnut extract, and geranium that target mitochondrial redox pathways, but statement that its dual mitochondrial–epigenetic action whitethorn connection a broader protective profile.