Animal welfare in diabetes research: a humane endpoint scoring system

Abstract

Humane endpoints are increasingly being used in animal experiments to ensure compliance with ethical regulations, namely the 3Rs policy. This study aimed to develop a clear humane endpoint (HE) scoring system for a streptozotocin (STZ)-induced diabetes model in male Sprague-Dawley rats. The rats were divided into a control (n=8) and an induced (n=16) group, with the latter receiving 10% fructose in their drinking water for 14 consecutive days. Following intraperitoneal administration of STZ (40 mg/kg) or 0.1 M citrate buffer, respectively, the following parameters were evaluated and scored: body weight, body posture, hair/tail appearance, grooming, grimace scale, mental status, response to external stimuli, hydration status, stool appearance, convulsions, and response to abdominal palpation. If the sum of the scores reached four or more, the animal was sacrificed. Additionally, several nutritional parameters, such as Lee index, body weight index (BWI), and abdominal and thoracic perimeters, were registered.