YY/T 1754.2-2020Preclinical animal study of medical devices - Part 2: Model of skin defect in induced diabetic rats (English PDF)

4.2 Reagents

4.2.2 Sodium citrate (analytical reagent)

One day after the successful establishment of the diabetic rat model, begin to establish the skin injury model. After anesthesia, place the rat on the operating table, with the back facing up; remove the back hair, to fully expose the back skin. After routine surgical disinfection, remove the 2 cm × 2 cm full-thickness skin from the back of the rat (other verified wounds are also available).

6.1.4 Test product sampling

The test rats should be randomly divided into a blank control group, a test product group, and/or a control product group (such as a commercially available product); the number of each group shall meet the requirements of statistical analysis. For the blank control group, only use sterile gauze/applicator to cover the skin wound on the back of the rat and fix, without other treatment; for the test product group and/or control group, use the relevant test product and/or control substance to cover the skin would on the back of the rat, and use sterile gauze/applicator to cover and fix. All animals are raised in single cages.

Observe the activities and diet of the animals every day, and replace the litter in time.

6.2 Test result and evaluation

6.2.1 General

The recommended observation period is at least 21 days. Select a reasonable observation time point according to the product characteristics. At least include the observation indicators of 6.2.2 ~ 6.2.4.

6.2.2 General wound recovery

It is advisable to roughly judge the recovery of the wound through the exudation, adhesion and wound retraction of the rat's wound.

6.2.3 Wound healing rate

The time point should be observed after the operation; take pictures of the wound; use image processing software or other verified software to measure the wound area. Wound healing rate is the ratio of the difference between the original wound area and the unhealed area of the wound to the original wound area. See Formula (1) for the calculation of wound healing rate:

Where: R -- Wound healing rate;

A0 -- Original area of the wound, in square centimeters (mm2);