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YY/T 1680-2020 PDF in English

YY/T 1680-2020 (YY/T1680-2020, YYT 1680-2020, YYT1680-2020)
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YY/T 1680-2020English170 Add to Cart 0-9 seconds. Auto-delivery. Allogeneic grafts--In vivo evaluation of osteoinductive potential for materials containing demineralized bone Valid

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Standards related to: YY/T 1680-2020

YY/T 1680-2020: PDF in English (YYT 1680-2020)

YY/T 1680-2020
ICS 11.040.40
C 45
Allogeneic Grafts - In Vivo Evaluation of
Osteoinductive Potential for Materials Containing
Demineralized Bone
Issued by: National Medical Administration of Traditional Chinese
Table of Contents
Foreword ... 3
Introduction ... 4
1 Scope ... 5
2 Normative References ... 5
3 Terms and Definitions ... 5
4 Animal Model ... 6
5 Test Procedures ... 8
6 Judgment of Results ... 11
7 Report Contents ... 12
Bibliography ... 13
Allogeneic Grafts - In Vivo Evaluation of
Osteoinductive Potential for Materials Containing
Demineralized Bone
1 Scope
This Standard provides methods and guidelines for evaluating the effectiveness of
allogeneic demineralized bone products in causing or promoting bone formation when
implanted (or injected) into the human body.
This Standard is applicable to the evaluation of osteoinductive performance of
demineralized bone and medical device products containing demineralized bone.
NOTE: Bone implants containing human gene recombinant BMP protein can also refer to this
Standard for the evaluation of in vivo osteoinductive performance.
2 Normative References
The following documents are essential to the application of this document. For the
dated documents, only the versions with the dates indicated are applicable to this
document; for the undated documents, only the latest version (including all the
amendments) is applicable to this document.
GB/T 16886.2 Biological Evaluation of Medical Devices - Part 2: Animal Welfare
YY/T 0513.3 Allogeneic Grafts - Part 3: Demineralized Bone Grafts
3 Terms and Definitions
For the purpose of this document, the terms and definitions given in YY/T 0513.3 and
the following apply.
3.1 Materials containing demineralized bone
Including but not limited to demineralized bone matrix, growth factors, differentiation
factors, biologically active carriers and/or non-biologically active carriers.
cytotoxic effector cells and graft-versus-host reaction. Therefore, there is no T cell
response to exogenous materials.
NOTE 1: Athymic animals can still produce an innate immune response (macrophages, giant
cells and granular red blood cells), therefore, have the ability to produce an immune response
to non-biocompatible or microbial (culture) positive products.
NOTE 2: The choice of nude rat or nude mouse as the experimental animal model depends on
the size (volume) of the implant to be evaluated.
4.2.2 Male athymic animals should be used in implantation experiments. If female
animals are used, it is necessary to prove that their estrus cycle shall not negatively
affect the experiment.
4.2.3 Adolescent athymic animals should be used in implantation experiments (age at
the time of implantation is 6 ~ 9 weeks). Older animals may not respond effectively to
osteoinductive materials.
4.3 Heterotopic implantation site
In athymic mouse/rat models, the intermuscular pocket spaces of the gluteal muscle
or biceps femoris are suitable implant sites. In clinical applications, there are blood,
bone tissue and osteogenic components at the bone tissue implantation site; while the
blood, bone tissue and osteogenic components shall cause false positive results
during heterotopic implantation.
4.4 Number of implants and sample volume/mass
4.4.1 Number of implants: In the product effectiveness test, 3 independent batches of
products should be used for testing. It is recommended to use 3 animals for each batch
of products; each animal has 2 implantation sites. The positive control and the negative
control are implanted into 3 animals, respectively; and each animal has 2 implantation
sites. So that ensure that each group shall have no less than 4 samples for evaluation.
NOTE: This design can obtain 83% inclusion probability within the 95% inclusion interval. This
allows a 12% difference in the detection of new bone formation. The hypothesis is as follows:
newly-formed bone accounts for 40%; the standard deviation is 5%; the statistical significance
level is 0.05.
4.4.2 Sample volume/mass: Generally, the mass of the implanted sample containing
demineralized bone material is (15±5) mg; and the size of the implanted sample should
be 3mm~5mm in length, 3mm~5mm in width, and 1mm~3mm in thickness (powder or
granular materials can be added with excipients; and the used excipients shall not
contain minerals and osteogenic active substances, which shall not affect the
osteoinductive ability of the raw materials).
4.4.3 The test group shall have the same implant dose and shape of demineralized
for subsequent implantation operations. The technician shall monitor the animal's
breathing during the operation.
5.3.5 Place the anesthetized animal in the prone position on the clean test bench in
the operating room and fix it. Wipe the animal back and waist area with iodine solution
from the center of the operation to the edge of the operation; and finally wipe off the
iodine solution with a clean sterile gauze pad.
5.3.6 The detailed procedures of the gluteus medius and gluteus maximus
intermuscular implantation are as follows: Carefully lift the skin above the spine at the
back and waist; and make a 0.5cm~1cm long unidirectional incision. Open the skin
incision and use the blunt peeling method to create a small pocket gap in the gluteus
medius and gluteus maximus tissue parallel to the direction of the muscle fibers, taking
care to avoid blood vessels. If there is a small amount of bleeding, stop the bleeding
in time and try to remove the blood. The sample is implanted in the gap between the
gluteus medius and the gluteus maximus intermuscular. After implantation, suture the
muscle layer. Use the same method to implant other test or control samples in the gap
between the gluteus medius and gluteus maximus on the other side. Finally, suture the
skin layer.
NOTE: When implanting the sample, pay attention to prevent the sample from contacting blood.
For example, try to avoid bleeding during the operation. If accidentally bleeding, try to compress
the bleeding and clean the blood residue before implanting the sample. When suturing after
surgery, the inserting position of the sutures shall be as far away as possible from the sample.
5.4 Postoperative treatment of animals
5.4.1 Put the animal back into the breeding cage and raise it separately.
5.4.2 Observe and record the health of the animals once a day after the operation. The
health status of the animal may be judged by direct contact with the animal or
observation outside the cage. If abnormal clinical symptoms or symptoms of
inflammation and infection are observed, corresponding treatment shall be carried out
as soon as possible.
5.4.3 If the experimental animal died during the experiment, the animal is required to
be autopsy. If the animal died after 14d (including 14d) after operation, the implantation
site and surrounding tissues shall be removed and fixed until its potential use in
histological research is determined. If the animal died within 14d after the operation,
an autopsy was performed. The final weight of the animal shall be recorded each time.
5.5 Methods of collecting materials
5.5.1 Collect materials at the designed time point; and record the final weight, health
status, and whether there are abnormal conditions of each experimental animal before
collecting the materials.
5.5.2 Touch the implant area to determine the approximate implant position. Use a
scalpel to make a longitudinal incision in the gluteus medius. Observe whether there
is blood outflow from the operation site. If there is blood outflow, perform hemostasis
treatment first.
5.5.3 Remove the fascia, sharply separate the tissue around the muscle and take out
the muscle as a whole. If the implanted material migrates away from the muscle tissue,
the observations are recorded in detail for subsequent analysis of the impact of sample
migration on the osteoinduction process. For example, when the implant migrates near
the bone tissue of the experimental animal, it shall cause false positive results.
5.5.4 Remove irrelevant tissue around the implant.
5.5.5 Record any abnormal color or shape of the muscle and implant, and/or the
condition of the implant and the connected muscle tissue. To avoid tissue dehydration,
place the sample in a tissue box or specimen bottle containing 8~10 times the volume
of neutral buffered formalin and fix it for at least 72h. Or put the sample into the tissue
box and freeze and fix the specimen quickly.
5.6 Histological evaluation of samples
5.6.1 The samples were frozen sectioned by quick freezing, or fixed by routine
histological staining procedures. After fixation, perform decalcification (if necessary),
dehydration, embed in paraffin or other media and trim. Before embedding, cut the
sample in half along the long axis; and embed the tissue block with the section facing
downward. The thickness of the slices is generally 4μm~7μm. They are spread out on
a glass slide and made into slices. Each slice contains at least 3 different sections.
Then choose the best new bone formation observation method to stain the slices. The
dyeing methods are: hematoxylin-eosin staining (HE), toluidine blue staining, alcian
blue staining, masson trichrome staining, Goldner trichrome staining and Von Kossa
staining. If using Von Kossa staining, special attention shall be paid to distinguish
stains and calcification of new bone.
5.6.2 At least 3 slices are prepared for each sample; and the slices with the least
wrinkles, the most uniform staining, and the largest amount of implant material are
used for the evaluation of osteoinductive ability.
5.6.3 Insert a 5×5 (24mm2) grid into the eyepiece of the microscope. Athymic mouse
implant sample slices are observed by using a 10x objective lens, with a total
magnification of 100 times; and athymic rat sample slices are observed by using a 4x
objective lens, with a total magnification of 40 times. When placing the specimen on
the stage, adjust the position of the sample slice so that the objective lens is above
one of the four corners of the sample slice. Check each field of view until the entire
sample slice is observed. A field of view is the area that can be observed within a 5×5
grid under 100/40 times magnification. If it is impossible to determine whether there is
bone formation in a specific division area, use a high magnification objective lens to
Source: Above contents are excerpted from the PDF -- translated/reviewed by: www.chinesestandard.net / Wayne Zheng et al.