The animal hypoxia experimental system is an important tool for studying the physiological and pathological mechanisms under hypoxic environments, and its standardized use directly affects the reliability of experimental data and animal welfare. The following outlines the core usage points from four aspects: equipment preparation, parameter control, process management, and security assurance.
1、 Preparation and adaptation before the experiment
1. Verification of cabin sealing
-Negative pressure test is required before use: after closing all channels, start the vacuum pump. Within 3 minutes, the cabin pressure should drop below -50kPa and remain stable, indicating no leakage points.
-Check whether the sealing rings of the observation window and gas inlet and outlet valves are aging, and replace the fluororubber seals if necessary.
2. Animal adaptive domestication
-Newly enrolled animals must adapt to a normal air environment for at least 48 hours and be free to eat and drink water;
-Adjust the size of the loading platform according to species characteristics (such as no more than 5 mice per cage, and independent ventilated cages for rats);
-Special strains require pre experimental confirmation of basal metabolic rate to avoid masking the true hypoxic effects due to stress reactions.
3. Gas ratio preset
-Using a mass flow meter to accurately control the N ₂/O ₂ mixing ratio, commonly used gradients are set as normoxic (21% O ₂), moderate hypoxia (10% -15%), and severe hypoxia (<6%);
-Equipped with CO ₂ absorbent (Soda Lime) and ammonia adsorption device to maintain harmful gas concentration<0.01% in the cabin.
2、 Process Management and Data Collection
1. Behavioral synchronous observation
-Install high-definition cameras combined with AI recognition systems to automatically calculate indicators such as activity level and respiratory rate;
-Record weight changes during daily scheduled unboxing and replacement of cushioning materials, and control the operation time within 5 minutes.
2. Physiological signal acquisition
-Implantable telemetry chip can obtain real-time heart rate and blood oxygen saturation data;
-Tail vein blood collection must strictly follow the 'three identical principles': same time point, same limb, and same operator.
3. Emergency plan configuration
-Reserve portable oxygen cylinders (flow rate adjustable to 0.5L/min), and keep emergency medical supplies within easy reach of the cabin;
-Set dual alarm threshold: When O ₂<8% or the cabin pressure suddenly changes>5kPa/min, the door will automatically release pressure and open.
3、 Ethics and Quality Control
1. Implementation of 3R principle
-Determine the minimum effective sample size through preliminary experiments and use stratified random grouping;
-Develop a progressive oxygen reduction program (daily reduction of 2% -3% O ₂) to alleviate acute stress reactions;
-Establish humane endpoint criteria: terminate the experiment immediately upon sustained convulsions and disappearance of corneal reflexes.
2. Comparison with setting standards
-In addition to the normoxic control group, an intermittent hypoxia group (such as 4-hour hypoxia+20 hour reoxygenation per day) was added;
-The animals in the control group and experimental group were sourced from the same period and batch, and were raised in the same environment.
3. Equipment maintenance cycle
-Monthly calibration of oxygen sensors (using standard gas calibration);
-Clean up the dust inside the cabin every quarter and replace the intake filter;
-Annual maintenance focuses on checking the response time of solenoid valves and the mechanical structure of sealing doors.