Ovalbumin [9006-59-1]

• Modeling Mechanism：

  Ovalbumin (OVA), as an allergen, induces a specific immune response in the body through a "sensitization-challenge" process: In the sensitization phase, it activates T helper 2 (Th2) cell polarization, promotes the secretion of cytokines such as IL-4 and IL-5, and stimulates B cells to produce OVA-specific IgE; In the challenge phase, re-exposure to the allergen triggers degranulation of mast cells and eosinophils, releasing inflammatory mediators such as histamine and leukotrienes, while activating the TLR4/NF-κB/COX2/NOS2 signaling pathway, inducing chronic airway inflammation, mucus hypersecretion, airway smooth muscle proliferation and remodeling, mimicking the pathological features of clinical T2-high asthma (eosinophil infiltration, IgE-mediated immediate hypersensitivity reaction).

• Related Products：

  Ovalbumins (T64744)

• Modeling Method：

  Experimental Subject：

  Rats, Sprague Dawley, Male, 250–300 g

  Dosage and Administration Route：

  ① Sensitisation phase: 10 mg Ovalbumin+300 mg aluminium hydroxide (Al(OH)₃, adjuvant), dissolved in 100 mM phosphate buffer (PB) pH 7.4, administered intraperitoneally on Day 1 and subcutaneously on Day 7;
  ② Challenge phase: 5% Ovalbumin solution, 50 μL per animal, intratracheal injection (ip), Pre-challenge sedation with 35 mg/kg sodium pentobarbital, analgesia with 10 mg/kg tramadol;
  ③ Control group: Sham-operated group substituted Ovalbumin with equal volume of PB, with all other procedures identical;

  Dosing Frequency and Duration Model：

  ① Sensitisation phase: Intraperitoneal injection on day 1 and subcutaneous injection on day 7, each administered once;
  ② Provocation phase: Intratracheal injection (ip) on days 14, 17, and 21

• Validation：

  1. Functional and Physiological Indicators: - Blood Gas Analysis: Elevated CO₂ concentration in arterial/venous blood, indicating hypoxemia; - Blood Indicators: Increased total white blood cell count (approximately 50%), with significant eosinophil infiltration; - Lung Function Related: Increased myeloperoxidase (MPO) activity in lung tissue (approximately 35%), reflecting inflammatory cell infiltration; 2. Molecular Indicators: - Inflammatory Factors: Upregulated expression of pro-inflammatory factors such as IL-1β, INF-γ, and IL-5 mRNA in lung tissue, and increased expression of anti-inflammatory factors such as IL-4 and IL-10, with the IL-4/INF-γ ratio increasing to 4 times that of the control group; - Signaling Pathways: Upregulated expression of TLR4, NF-κB, COX2, NOS2, and the macrophage marker CD68 protein by 2-4 times; - Remodeling Markers: Significantly increased expression of α-smooth muscle actin (α-SMA) and type I collagen (COL1A1) protein; 3. Pathological indicators: - Histological morphology: HE staining showed airway epithelial damage and interstitial inflammatory infiltration; PAS-toluidine blue staining showed goblet cell proliferation and increased mucus secretion; - Fibrosis: Masson trichrome staining showed peri-airway collagen deposition, airway wall thickening, and smooth muscle proliferation.

*Precautions： Animals were euthanized 2 hours after the last challenge with sodium pentobarbital (90 mg/Kg ip).

*References：Mundo-Franco Z,et,al. C-Phycocyanin Prevents Oxidative Stress, Inflammation, and Lung Remodeling in an Ovalbumin-Induced Rat Asthma Model. Int J Mol Sci. 2024 Jun 27;25(13):7031.