Buloxibutid hydrochloride
Based on 7 publication(s) in Google Scholar
Buloxibutid (AT2 receptor agonist C21) hydrochloride is an orally active, selective angiotensin II type 2 receptor (AT2R) agonist, with a Ki value of 0.4 nM for porcine AT2R. Buloxibutid hydrochloride exerts vasodilatory, anti-inflammatory, antifibrotic (promoting the expression of collagenase MMP-13) and tissue repair effects mainly by activating the NO/cGMP pathway, inhibiting the pro-proliferative MAPK signaling, and suppressing the pro-fibrotic TGF-β/Smad pathway and inflammatory NF-κB pathway. Buloxibutid hydrochloride can be used in research related to idiopathic pulmonary fibrosis, hypertension, systemic sclerosis and other conditions.
For research use only. We do not sell to patients.
- CAS No.: 1947313-60-1
- Formula: C23H30ClN3O4S2
- Molecular Weight:512.09
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Storage:
Please store the product under the recommended conditions in the Certificate of Analysis.
Publications Citing Use of MedChemExpress (MCE) Buloxibutid hydrochloride
More- Acta Pharmacol Sin. 2024 Jun;45(6):1201-1213. [Abstract]
- Clin Sci. 2022 Jun 30;136(12):989-1003. [Abstract]
- Cell Mol Life Sci. 2025 Apr 18;82(1):165. [Abstract]
- Eur J Pharmacol. 2023 Feb 15:941:175466. [Abstract]
- Biomolecules. 2026 Jul 17;16(7):1042.
- SSRN. 2026 May 7.
- Dokkyo Medical Journal. 2023 Sep 8.
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In Vivo Efficacy Study
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Histological Imaging/Staining
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WB
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Bio/Physico-chemical Assay
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IF
All Angiotensin Receptor Isoforms
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Biological Activity
Description
IC50 & Target
[4]|
AT2 Receptor 0.4 nM (Ki) |
AT1 Receptor > 10 μM (Ki) |
In Vitro
Buloxibutid (1-10 μM) hydrochloride inhibits the expression and signaling of proinflammatory pathways in LPS (HY-D1056)-induced THP-1 macrophages in a time- and concentration-dependent manner at concentrations of 1 and 10 μM[2].
Buloxibutid (Compound 21) (0.1-0.1 μM; 3 days) hydrochloride induces neurite outgrowth in NG108-15 cells by activating AT2 receptors. After treatment with 0.1 μM for 3 days, it increases the proportion of neurite-positive cells to 19.9%, and its signal transduction depends on the MAPK, cGMP and cGMP-dependent protein kinase pathways[4].
Buloxibutid (100 nM; 0-1 h) hydrochloride transiently activates p42/p44mapk in NG108-15 cells via activation of the AT2 receptor, and its phosphorylation level increases by 2.2-fold after treatment with 0.1 μM for 30 min[4].
MedChemExpress (MCE) has not independently confirmed the accuracy of these methods. They are for reference only. Further protocols information, click here.
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Cell Line:NG108-15 neuroblastoma-glioma hybrid cells
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Concentration:0.1 nM, 1 nM, 0.1 μM, 1 μM
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Incubation Time:3 days
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Result:Increased the percentage of neurite-positive cells from 5.5% (control) to 19.9% at 0.1 μM treatment.
Induced neurite outgrowth at concentrations ≥ 0.1 nM.
Had its neurite outgrowth effect abolished by co-incubation with PD 123,319.
Had its neurite outgrowth effect reduced by co-incubation with PD 98,059, LY-83,583, or KT 5823.
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Cell Line:NG108-15 neuroblastoma-glioma hybrid cells
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Concentration:100 nM
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Incubation Time:0, 30 and 60 min
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Result:Induced a 2.2-fold increase in phosphorylated p42/p44mapk levels relative to control within 30 min.
Decreased phosphorylated p42/p44mapk levels to basal levels by 60 min.
Had its 30-min activation abolished by pre-incubation with PD 123,319.
In Vivo
Buloxibutid (0.3 mg/kg/day; mini pump; daily administration; for 7 consecutive days) hydrochloride alleviates bleomycin-induced pulmonary fibrosis in rats[2].
Buloxibutid (1 mg/kg; i.p.; single administration) hydrochloride attenuates lung injury and inflammation induced by ventilator-induced lung injury (VILI) in Sprague-Dawley rats[2].
Buloxibutid (0.3 mg/kg/day; i.p.; daily) hydrochloride alleviates LPS-induced acute lung injury in C57Bl/6 mice[2].
Buloxibutid (0.3 mg/kg/day; i.p.; daily administration) hydrochloride alleviates hyperoxia-induced acute lung injury in C57Bl/6 mice[2].
Buloxibutid (0.1-1 mg/kg/day; i.p.; administered daily for 7 consecutive days) hydrochloride reduces acute cigarette smoke-induced inflammation in female BALB/c mice, with the maximum efficacy observed at a dose of 0.3 mg/kg/day[2].
Buloxibutid (0.3 mg/kg/day; i.p.; daily administration; for 3 consecutive weeks) hydrochloride reduces chronic cigarette smoke-induced inflammation, epithelial injury and profibrotic responses, while improving pulmonary function in BALB/c mice[2].
Buloxibutid (0.03 mg/kg/day; i.p.; daily administration for 2 consecutive weeks) hydrochloride reverses monocrotaline-induced pulmonary fibrosis and myocardial fibrosis in male Sprague-Dawley rats[2].
Buloxibutid (0.03 mg/kg; i.p.; once daily; for 14 consecutive days) hydrochloride significantly reduces systolic blood pressure, diastolic blood pressure, and mean blood pressure by 34.4%, 40.2%, and 38.0%, respectively, in male Sprague Dawley rats with hypertension induced by L-NAME/NaCl. It also improves the antioxidant status of the heart and aorta, alleviates histopathological damage to cardiac tissue, and restores normal aortic structure[3].
Buloxibutid (0.03 mg/kg; i.p.; daily; 14 days) hydrochloride combined with Empagliflozin (HY-15409) significantly improves the antioxidant status of the heart and aorta in male Sprague Dawley rats with hypertension induced by L-NAME/NaCl, reduces aortic MDA levels by 27.5%, restores normal aortic structure, alleviates cardiac histopathological damage, and exerts a synergistic effect on aortic SOD and CAT activities[3].
Buloxibutid (Compound 21) (0.003-0.3 mg/kg/h; i.v.; continuous infusion; 100 μM; intraluminal perfusion) hydrochloride dose-dependently enhances duodenal mucosal alkaline secretion in male Sprague-Dawley rats via activation of the AT2 receptor, with the maximal effect observed at an intravenous dose of 0.3 mg/kg/h[4].
Buloxibutid (0.008-4 mg/kg; i.v.; single bolus) hydrochloride induces a significant AT2 receptor-mediated reduction in mean arterial pressure at intravenous doses of 0.008 mg/kg and 0.05 mg/kg in anesthetized spontaneously hypertensive rats[4].
MedChemExpress (MCE) has not independently confirmed the accuracy of these methods. They are for reference only.
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Animal Model:Sprague-Dawley[2]
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Dosage:0.03 mg/kg/day
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Administration:i.p.; daily; 14 days
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Result:Attenuated bleomycin-induced increases in right ventricular systolic pressure (RVSP), associated with reduced cardiac and pulmonary vascular remodeling.
Caused significant reductions in percentage fibrotic area, Ashcroft score, and hydroxyproline content.
Prevented or reversed bleomycin-induced increases in Col1a/3a1, CTGF, MMP-12, TIMP-1, and IL-13 gene expression to baseline levels.
Reduced pro-inflammatory gene expression (CCL2, IL-6, TLR4) and CD68+ macrophage infiltration.
Reduced bleomycin-induced increases in AT2R gene expression.
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Animal Model:Sprague-Dawley[2]
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Dosage:0.3 mg/kg/day
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Administration:subcutaneous; daily; 7 days
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Result:Reduced bleomycin-induced increases in Ashcroft score and percentage interstitial collagen area, slightly more effectively than β-Pro7 Ang III, and with greater efficacy than pirfenidone for these fibrotic measures.
Reduced lung myofibroblast accumulation and TGFβ expression to a similar degree as β-Pro7 Ang III and pirfenidone.
Tended to increase lung compliance relative to the bleomycin group.
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Animal Model:Sprague-Dawley[2]
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Dosage:1 mg/kg
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Administration:i.p.; single dose
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Result:Significantly attenuated ventilation-induced lung damage (histological scoring).
Reduced cell and protein content in bronchoalveolar lavage fluid (BALF).
Caused a significant increase in the anti-inflammatory cytokines IL-4 and IL-10.
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Animal Model:BALB/c (female)[2]
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Dosage:0.1 mg/kg/day; 0.3 mg/kg/day; 1 mg/kg/day
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Administration:i.p.; daily; 7 days
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Result:Exhibited dose-dependent anti-inflammatory effects, reducing cytokines and cells in BALF, with maximal effects observed at the 0.3 mg/kg dose.
Restored alveolar macrophage phagocytic ability at 0.3 mg/kg/day.
Suppressed cigarette smoke-induced pro-inflammatory marker expression at 0.3 mg/kg/day.
Restored M2 phenotypic marker expression at 0.3 mg/kg/day.
Upregulated AT2R and MasR expression at 0.3 mg/kg/day.
Reversed cigarette smoke-induced reductions in AT2R expression.
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Animal Model:BALB/c (female)[2]
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Dosage:0.3 mg/kg/day
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Administration:i.p.; daily; 21 days
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Result:Significantly reduced cigarette smoke-induced increases in pro-inflammatory cytokines and alveolar epithelial thickening.
Opposed pro-fibrotic responses, reducing active TGFβ1, SMAD2/3, hydroxyproline, MMP-9, and MMP-12 levels, though augmented cigarette smoke-induced increases in TIMP-1.
Elicited significant protective effects in all measured lung function parameters.
Reversed cigarette smoke-induced increases in AT2R expression.
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Animal Model:Sprague-Dawley (male)[2]
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Dosage:0.03 mg/kg/day
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Administration:i.p.; daily; 14 days
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Result:Reversed lung interstitial and peri-vascular fibrosis, as well as cardiac fibrosis; this anti-fibrotic effect was abrogated by co-administration with an AT2R antagonist or MasR antagonist.
Reversed monocrotaline-induced increases in ACE gene expression and decreases in ACE2 gene expression, restoring ACE2 to double control levels.
Did not affect AT1R expression but significantly increased AT2R expression relative to monocrotaline-treated and control rats.
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Animal Model:Not specified[2]
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Dosage:2 mg/kg/day; 20 mg/kg/day
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Administration:p.o.; daily; 34 days
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Result:Significantly improved cardiac function.
Reversed remodeling in vessels of all sizes.
Reduced lung collagen content and percentage dense area.
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Animal Model:Sprague Dawley (male, hypertension induced via 40 mg/kg L-NAME i.p. once daily for 28 days plus 1% NaCl in drinking water ad libitum for 28 days)[3]
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Dosage:0.03 mg/kg
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Administration:i.p.; once daily; 14 days
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Result:Reduced systolic blood pressure to a median of 73.77 mmHg, diastolic blood pressure to a median of 57.82 mmHg, and mean blood pressure to a median of 67.465 mmHg compared to the hypertension-only group.
Decreased heart rate to a median of 215.075 beats/min compared to the control group.
Reduced heart weight to a median of 1.177 g compared to the hypertension-only group.
Increased superoxide dismutase activity to a median of 6.303 U/g protein and glutathione peroxidase activity to a median of 79.698 U/mg protein in cardiac tissue compared to the hypertension-only group.
Increased glutathione level to a median of 51.333 μmol/g tissue, superoxide dismutase activity to a median of 16.511 U/g protein, catalase activity to a median of 42.085 K/g protein, and glutathione peroxidase activity to a median of 104.833 U/mg protein in aortic tissue compared to the hypertension-only group.
Increased serum calcium level to a median of 9.95 mg/dL and reduced serum total cholesterol level to a median of 38.5 mg/dL compared to the hypertension-only group.
Reduced cardiac histopathological damage scores for degenerated cardiomyocytes, hemorrhage, inflammatory infiltration, and collagen deposition compared to the hypertension-only group.
Restored thoracic aortic histology to a state similar to the control group, resolving dilatation and elastic lamella irregularities seen in the hypertension-only group.
Chemical Information
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CAS No. 1947313-60-1
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Molecular Weight 512.09
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Formula C23H30ClN3O4S2
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SMILES
O=C(NS(=O)(C1=C(C2=CC=C(CN3C=NC=C3)C=C2)C=C(CC(C)C)S1)=O)OCCCC.Cl
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Synonyms
AT2 receptor agonist C21 hydrochloride
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Shipping
Room temperature in continental US; may vary elsewhere.
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Storage
Please store the product under the recommended conditions in the Certificate of Analysis.
Publications (7)
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Journal Impact Factor
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Most Recent
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Acta Pharmacol Sin
Angiotensin II type-2 receptor signaling facilitates liver injury repair and regeneration via inactivation of Hippo pathway. [Abstract]2024 Jun;45(6):1201-1213. PMID: 38491160
Buloxibutid hydrochloride purchased from MedChemExpress. Usage Cited in: Acta Pharmacol Sin. 2024 Jun;45(6):1201-1213. [Abstract]
Representative images of liver tissue sections from wild-type mice (aged 10 days) treated with vehicle or C21 (Buloxibutid; i.p.) 0.3 mg/kg every 12 h for 10 days. The liver-to-body weight ratios were significantly higher in the treatment groups than in the vehicle groups.
Buloxibutid hydrochloride purchased from MedChemExpress. Usage Cited in: Acta Pharmacol Sin. 2024 Jun;45(6):1201-1213. [Abstract]
Immunohistochemical analysis of Ki-67, Yap, and BrdU expression levels in liver tissue sections from wild-type mice (aged 10 days) treated with vehicle or C21 (Buloxibutid; i.p.) 0.3 mg/kg every 12 h for 10 days.
Buloxibutid hydrochloride purchased from MedChemExpress. Usage Cited in: Acta Pharmacol Sin. 2024 Jun;45(6):1201-1213. [Abstract]
Immunoblot analysis of the indicated proteins in liver tissue sections from wild-type mice (aged 10 days) treated with vehicle or C21 (Buloxibutid; i.p.) 0.3 mg/kg every 12 h for 10 days. The results showed that p-Yap and p-LATS1 expression levels were significantly lower in the C21-treated groups than in the vehicle groups, suggesting a potential regulatory role for the AT2R in modulation of the Hippo–Yap signaling pathway.
Buloxibutid hydrochloride purchased from MedChemExpress. Usage Cited in: Acta Pharmacol Sin. 2024 Jun;45(6):1201-1213. [Abstract]
Serum alanine aminotransferase and aspartate aminotransferase levels in wild-type mice (n = 6) at 6 h after treatment with vehicle or C21 (Buloxibutid; 0.3 mg/kg; i.p.; single dose) following exposure to acetaminophen. At 6 h after administration of acetaminophen, serum ALT and AST levels were significantly lower in the C21-treated group than in the vehicle-treated control group.
Buloxibutid hydrochloride purchased from MedChemExpress. Usage Cited in: Acta Pharmacol Sin. 2024 Jun;45(6):1201-1213. [Abstract]
Immunofluorescence staining of F-actin (red), Yap (green), and DAPI (blue) in AML12 cells treated with C21 (Buloxibutid; 10 μM; 24 h). The result indicated a correlation between cellular F-actin abundance and the nuclear localization of Yap.
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Clin Sci
G-protein-coupled receptor kinase 4 causes renal angiotensin II type 2 receptor dysfunction by increasing its phosphorylation. [Abstract]2022 Jun 30;136(12):989-1003. PMID: 35695067 -
Cell Mol Life Sci
Involvement of miRNA-204 carried by the exosomes of macrophages in the AT2 receptor-mediated improvement of vascular calcification. [Abstract]2025 Apr 18;82(1):165. PMID: 40249512 -
Eur J Pharmacol
Activation of angiotensin II type 2 receptor attenuates lung injury of collagen-induced arthritis by alleviating endothelial cell injury and promoting Ly6Clo monocyte transition. [Abstract]2023 Feb 15:941:175466. PMID: 36528072 -
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Protocols
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Fibrosis/Collagen Morphometry
Fibrosis and collagen morphometry is based on the quantitative visualization of fibrillar collagen deposition in tissue sections using histochemical stains such as Sirius Red (Picrosirius Red) or Masson's trichrome, followed by image-based or polarization-enhanced analysis to estimate collagen proportional area as a surrogate of extracellular matrix accumulation during fibrotic remodeling. Sirius Red combined with polarized light microscopy enhances detection of collagen fibers due to birefringence properties, enabling more specific visualization of collagen type I and III fibrils compared to conventional bright-field histology, while whole-section or region-restricted digital morphometry reduces field-selection bias in fibrosis assessment. Alternative quantitative approaches include second harmonic generation (SHG) and two-photon excited fluorescence microscopy, which enable label-free detection of fibrillar collagen and have been validated against histological staining and biochemica
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RNA extraction experimental
By lysing cells, releasing RNA, and removing impurities such as proteins and DNA, high-purity RNA products are finally obtained. The commonly used traditional method is the guanidine isothiocyanate/phenol/chloroform method (Trizol), which is suitable for a variety of animal materials including animal tissues, microorganisms, cultured cells, etc., and most plant materials.
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Collagen: Sirius Red Staining
Sirius Red or picrosirius red staining is a histochemical method for visualizing collagen-rich extracellular matrix in tissue sections, and collagen fibers are detected as red-stained structures under bright-field microscopy with enhanced birefringence under polarized light. Picrosirius red is useful for assessing total collagen organization, distribution, and fibrosis burden, but polarized color should not be interpreted as a definitive collagen type I versus type III readout because color is affected by fiber orientation, thickness, and packing.
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Mitochondrial membrane-potential fluorescent assay
Mitochondrial membrane potential fluorescent assays estimate ΔΨm in living cells using lipophilic cationic dyes such as TMRM, TMRE, rhodamine 123, and JC-1, which accumulate in mitochondria according to membrane polarization; loss of signal after FCCP or CCCP treatment is interpreted as mitochondrial depolarization. TMRM/TMRE and rhodamine 123 are commonly used for semi-quantitative live-cell microscopy or flow cytometry, while JC-1 can report a shift from red aggregate fluorescence to green monomer fluorescence during depolarization; interpretation requires controls because dye concentration, quenching mode, cell type, dye efflux, and mitochondrial mass can affect fluorescence independently of ΔΨm.
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Connective Tissue: Masson's Trichrome/Collagen Trichrome Staining
Masson’s Trichrome (collagen/trichrome staining) is a histological technique that differentially stains tissue compartments using sequential acidic dyes to distinguish collagen from muscle and cytoplasmic components based on dye affinity and tissue permeability differences, enabling visualization of fibrosis and connective tissue architecture in histological sections. The classical formulation typically uses Weigert's iron hematoxylin for nuclear staining, Biebrich scarlet-acid fuchsin for cytoplasm and muscle, and aniline blue (or light green variants) for collagen, producing a characteristic blue/green collagen signal contrasted against red cytoplasm and dark nuclei. The staining principle relies on selective displacement of smaller dye molecules by larger anionic dyes in collagen-rich regions under controlled acidified conditions, which enhances collagen-specific dye retention. This property makes the method widely used for fibrosis assessment in organs such as heart, liver, lung, a
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Mitochondrial membrane-potential and mitochondrial mass staining
Mitochondrial membrane potential staining measures the electrochemical polarization across the mitochondrial inner membrane in live cells using lipophilic cationic fluorescent probes; early rhodamine-based work showed that selective mitochondrial dye accumulation is lost when the mitochondrial transmembrane potential is dissipated. JC-1 reports mitochondrial polarization by shifting from green monomer fluorescence to red J-aggregate fluorescence as dye concentration increases within energized mitochondria; therefore, the red/green fluorescence ratio is used as a relative readout of mitochondrial membrane potential. TMRE or TMRM staining provides a single-channel relative readout because these cationic rhodamine esters accumulate in polarized mitochondria, and lower fluorescence indicates reduced mitochondrial polarization when acquisition and dye-loading conditions are controlled. Mitochondrial mass staining is commonly performed with MitoTracker Green FM or related MitoTracker dyes as
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Research Protocol for Cardiovascular Diseases
Cardiovascular disease can be modeled as maladaptive cardiac remodeling, where ischemic injury or pressure overload activates inflammatory signaling, fibroblast activation, extracellular-matrix deposition, cardiomyocyte hypertrophy, vascular remodeling, and progressive ventricular dysfunction. The TGF-β/SMAD axis is a central profibrotic pathway after myocardial injury and pressure overload, while innate immune and cytokine pathways regulate leukocyte recruitment, scar formation, and adverse remodeling. Key unresolved questions include which inflammatory signals are reparative versus harmful, when fibrosis is protective versus maladaptive, and whether pathway inhibition improves function without weakening necessary infarct healing or compensatory remodeling.
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Research Protocol for Inflammation-related Diseases
The NLRP3 inflammasome is a cytosolic innate immune signaling platform that integrates priming signals and danger-signal activation to promote caspase-1 activation, maturation of IL-1β and IL-18, and gasdermin D-mediated pyroptotic cell death. The core experimental logic is to determine whether inflammatory disease phenotypes are driven by increased NLRP3 expression, ASC-containing inflammasome assembly, caspase-1 cleavage, GSDMD cleavage, and extracellular release of IL-1β/IL-18 rather than by nonspecific cell injury alone. The pathway is strongly linked to inflammation-related disease phenotypes because monosodium urate crystals activate NALP3/NLRP3 inflammasome signaling in gout-like crystal inflammation, cholesterol crystals activate NLRP3 inflammasomes in atherogenesis models, and DSS-induced intestinal inflammation has been reported to involve NLRP3 inflammasome activity. However, experimental colitis studies also show context-dependent protective effects of NLRP3 inflammasome co
Purity & Documentation
References
[1]. Rein-Hedin E, et al. Utilizing venous occlusion plethysmography to assess vascular effects: A study with buloxibutid, an angiotensin II type 2 receptor agonist. Clin Transl Sci. 2024;17(2):e13735. [Content Brief]
[2]. Young ON, et al. Investigational insights into the potential of angiotensin type II receptor agonists as therapeutics for idiopathic pulmonary fibrosis. Expert Opin Investig Drugs. 2026;35(1):63-73. [Content Brief]
[3]. Ozhan O, et al. Protective effects of buloxibutid and empagliflozin on hypertension-induced cardiac and vascular injury in rats. J Mol Histol. 2026;57(1):35. Published 2026 Jan 10. [Content Brief]
[4].
Wan Y, et al. Design, synthesis, and biological evaluation of the first selective nonpeptide AT2 receptor agonist. J Med Chem. 2004;47(24):5995-6008.
[Content Brief]
Calculators
Concentration (start) × Volume (start) = Concentration (final) × Volume (final)
Keywords
- Buloxibutid
- 1947313-60-1
- AT2 receptor agonist C21
- Angiotensin Receptor
- p38 MAPK
- TGF-β Receptor
- TGF-beta/Smad
- MMP
- Raynaud's phenomenon
- angiotensin II type 2 receptor
- systemic sclerosis
- C57Bl/6 mice
- AT2R
- BALB/c mice
- idiopathic pulmonary fibrosis
- hypertension
- THP-1 human macrophages
- Sprague-Dawley rats
- Inhibitor
- inhibitor
- inhibit