How are experiments conducted on rats? - briefly
Researchers house rats in standardized cages with regulated temperature, lighting, and diet. Experiments involve interventions such as drug dosing, surgical manipulation, or behavioral assays, all conducted under approved animal‑care protocols.
How are experiments conducted on rats? - in detail
Researchers begin rat studies by obtaining ethical clearance from institutional review boards, which require justification of animal numbers, minimization of discomfort, and adherence to the 3Rs (replacement, reduction, refinement). Animals are sourced from accredited breeders, screened for health status, and assigned a unique identifier to ensure traceability.
Prior to experimentation, subjects are housed in controlled environments: temperature maintained at 20‑24 °C, humidity 40‑60 %, a 12‑hour light/dark cycle, and enrichment items such as nesting material and tunnels. Bedding is changed regularly, and water and standard chow are provided ad libitum unless restricted by protocol. A habituation period of 5‑7 days allows animals to acclimate to the facility and handling procedures, reducing stress‑induced variability.
Experimental design follows strict randomization and blinding. Researchers allocate rats to treatment groups using computer‑generated random sequences, and personnel involved in data acquisition remain unaware of group assignments to prevent bias. Sample size calculations are performed in advance, based on expected effect size and statistical power.
Procedures are categorized by invasiveness:
- Non‑invasive assessments – body weight, temperature, locomotor activity measured with infrared sensors, and behavioral tests such as open‑field, elevated plus‑maze, or forced swim.
- Pharmacological interventions – substances administered via oral gavage, intraperitoneal injection, subcutaneous infusion, or osmotic minipumps. Doses are calculated per kilogram of body weight, and injection sites are sterilized to prevent infection.
- Surgical manipulations – anesthesia induced with isoflurane or injectable agents (e.g., ketamine/xylazine). Aseptic technique includes sterilized instruments, surgical drapes, and antimicrobial prophylaxis. Procedures may involve catheter implantation, stereotaxic brain targeting, or lesion creation. Post‑operative analgesia (e.g., buprenorphine) is provided according to analgesic protocols, and animals are monitored for recovery of righting reflex and normal respiration.
Physiological recordings employ telemetry or wired systems. Electrodes placed in cardiovascular or neural structures transmit real‑time data on heart rate, blood pressure, or neuronal firing patterns. Calibration is performed before each session, and signal quality is verified throughout the experiment.
Data collection follows predefined time points, documented in laboratory notebooks or electronic systems with timestamps. Raw data are backed up, and statistical analysis plans are pre‑registered to avoid selective reporting.
At study termination, humane euthanasia is carried out using approved methods such as CO₂ inhalation followed by secondary physical disruption, or overdose of anesthetic agents. Post‑mortem examinations may include organ harvesting, histological processing, and biochemical assays to confirm experimental endpoints.
All steps are recorded in Standard Operating Procedures, ensuring reproducibility and compliance with regulatory standards.