Description
Triglycerides (TG), also known as triacylglycerols, are fat molecules formed from three long-chain fatty acids and glycerol. They are the most abundant lipids in the human body. Most tissues can utilize the breakdown products of triglycerides for energy. Simultaneously, tissues like the liver and adipose tissue can synthesize triglycerides. The enzymatic method for measuring TG is commonly used in biochemical assays due to its characteristics: 1. High sensitivity, accuracy, and precision; 2. Use of mild reaction conditions; 3. Simple operation; 4. Suitable for semi-automatic biochemical analyzers.Detection Principle: Triglycerides are hydrolyzed by lipoprotein lipase (LPL) into glycerol and free fatty acids. Glycerol is then phosphorylated by glycerol kinase (GK) and adenosine triphosphate (ATP) to form glycerol-3-phosphate (G-3-P). G-3-P is subsequently oxidized by glycerol-3-phosphate oxidase (GPO), producing hydrogen peroxide. The hydrogen peroxide, in the presence of peroxidase (POD), 4-aminoantipyrine (4-AAP), and phenol (collectively known as PAP), reacts to form a red-colored quinoneimine dye (Trinder reaction). The quinoneimine dye has a maximum absorption at 510 nm. The absorbance is directly proportional to the triglyceride concentration in the sample and can be measured using a microplate reader between 500-520 nm.This kit is used for the quantitative determination of triglyceride content in serum, cells, tissues, and other samples from humans or animals. This kit is intended for research use only and is not suitable for clinical diagnosis or other purposes.Component100TStorageBuffer Solution24 mL2-8℃. Store in the dark.Enzyme Reagent6 mL2-8℃. Store in the dark.Glycerol Standard (1.7 mmol/L)1 mL2-8℃User-Prepared Instruments and ReagentsddH₂O, Physiological Saline or PBSCentrifuge tubes or small test tubes, Water bath or incubatorMicroplate reader, 96-well plate, Semi-automatic biochemical analyzerExperimental Procedure1. Sample Preparation1.1 Serum, Plasma, Cerebrospinal Fluid SamplesSerum or plasma separated from the test sample should not be hemolyzed. Assay directly. If the concentration exceeds the linear range, dilute with physiological saline before assaying.1.2 Cell Samples(1) Take an appropriate amount of cells (generally recommended >10⁶), centrifuge at 1000 g for 10 min, discard the supernatant, keep the pellet.(2) Wash the pellet 1-2 times with PBS or physiological saline, centrifuge at 1000 g for 10 min, discard the supernatant, keep the pellet.(3) Add 200-300 µL of PBS or physiological saline to homogenize. Sonicate the cells on ice (power 300W, pulse 3-5s, interval 30s, repeat 3-5 times). Alternatively, homogenize manually. Do not centrifuge the prepared homogenate. Alternatively, lyse with 1-2% Triton X-100 on ice for 30-60 min. Do not centrifuge the prepared lysate.1.3 Tissue SamplesAccurately weigh an appropriate amount of tissue sample. Add physiological saline or PBS at a mass (g) to volume (mL) ratio of 1:9. Homogenize manually or mechanically on ice. Centrifuge at 2500-3000 g for 10 min. Collect the supernatant for assay.2. Preparation of GPO-PAP Working SolutionBefore use, mix the Buffer Solution and Enzyme Reagent at a 4:1 volume ratio. Mix well. Store at 4°C.3. TG Assay Steps using Microplate Reader3.1 Add reagents sequentially to the 96-well plate according to the table below. Mix thoroughly and incubate at 37°C in a water bath or incubator for 10 minutes.Reagent (µL)Blank WellStandard WellTest WellddH2O2.5//Glycerol Standard (1.7 mmol/L)/2.5/Test Sample//2.5GPO-PAP Working Solution2502502503.2 Measure the absorbance between 500-520 nm using the microplate reader. Zero the instrument with the blank well, then read the absorbance of the standard well and all test wells.4. TG Assay Steps using Semi-Automatic Biochemical Analyzer4.1 Instrument Parameter Settings:WavelengthTemperatureDelay TimeMeasurement TimeReagent BlankReaction TypeAspiration Volume510-550nm37℃2s2sYesEndpoint800µL4.2 Add reagents sequentially to tubes according to the table below. Mix thoroughly and incubate at 37°C in a water bath for 10 minutes.Reagent (µL)Blank TubeStandard TubeTest TubeddH2O10//Glycerol Standard (1.7 mmol/L)/10/Test Sample//10GPO-PAP Working Solution1000100010004.3 Zero the instrument with the blank tube, then read the absorbance of the standard tube and all test tubes.5. Calculation Formula5.1 For serum, plasma, and other liquid samples (Blank zeroed):TG (mmol/L) = (Absorbance of Test Well/Tube / Absorbance of Standard Well/Tube) × 1.7 mmol/L5.2 For cell, tissue, and other samples (Blank zeroed):TG (mmol/g prot) = (Absorbance of Test Well/Tube / Absorbance of Standard Well/Tube) × 1.7 mmol/L / Sample Protein Concentration (mg/mL)Reference Interval (Healthy Adults)Desirable range: < 1.7 mmol/L (< 150 mg/dL)Borderline high: 1.7 – 2.25 mmol/L (150 – 199 mg/dL)High: 2.26 – 5.64 mmol/L (200 – 499 mg/dL)Very high: ≥ 5.65 mmol/L (≥ 500 mg/dL)Precautions1. Avoid repeated freeze-thaw cycles for the low-temperature reagents mentioned above to prevent inactivation or decreased efficiency.2. The GPO-PAP Working Solution should be prepared immediately before use and is not suitable for long-term storage at 4°C.3. This method can be directly used to detect TG content in cerebrospinal fluid but cannot directly detect TG in urine, as untreated urine contains reducing substances that interfere with the peroxidase reaction.4. If test samples cannot be assayed immediately, they should be stored at 2-8°C and are stable for 3 days.5. The linear range of this method is up to 9.0 mmol/L. If the sample TG concentration is too high, results may be falsely low. Dilute the sample with physiological saline and re-assay, multiplying the result by the dilution factor.6. The working reagent should be protected from contamination by substances like glucose and cholesterol.7. The reagent is susceptible to oxidation by air, turning red. A blank measurement is necessary.8. For your safety and health, please wear a lab coat and disposable gloves during operation.9.Use the reagents as soon as possible after opening to prevent affecting subsequent experimental results