Abstract: BACKGROUND: Absorbable hemostatic materials are currently a hot field of hemostatic materials. The clinical demand for safe and effective absorbable hemostatic materials is increasing. Fish scale collagen is not only safe and effective, but also can turn fish scales into treasures and make full use of resources reasonably.
OBJECTIVE: To verify the hemostatic efficacy, the degradation procedure in vivo, and explore the safety of fish scale collagen.
METHODS: Fish scale collagen material was extracted by chemical decalcification combined with low temperature enzymatic method, and used in the following three tests. (1) The First Part: The bleeding test included the body-liver bleeding and surface-tail bleeding. Liver bleeding and tail hemorrhage model was prepared by physical damage to the liver and tail. Model animals were divided into experimental group (use of fish scale collagen), the control group (use of hemostatic sponge), and blank group (no processing). The amount of blood loss and hemostatic time were recorded. (2) Part II: In vivo degradation test of fish scale collagen: Animals with liver hemostasis were euthanized at 1, 3, 5, 10, 20, 30, 40, 50, and 60 days after being filled with fish scale collagen material. Animals in the control group were euthanized at 5 and 50 days after being filled with hemostatic sponge. Animals in the blank group were euthanized at 5 and 50 days after modeling. The adhesions in abdominal cavity were observed, and the degradation of material and the progress of liver regeneration were observed pathologically. (3) Part III: Biological evaluation, including hemolysis test, epidermal stimulation test, intradermal stimulation test, pyrogen test, and acute toxicity test.
RESULTS AND CONCLUSION: (1) The collagen of filamentous fish scale was extracted successfully by chemical decalcification combined with low temperature enzymatic method; the yield was 66%-73%, and the pore size of collagen of fish scale was 0.80±0.23 mm. (2) Tail bleeding model was used to verify the hemostatic effect of body surface. Compared with the blank group, the hemostatic time of fish scale collagen was significantly shortened, and the amount of blood loss was significantly reduced compared with the control group (hemostatic sponge) and the blank group (P < 0.05). (3) At 5 days after implantation, the collagen of fish scale was closely attached to the damaged liver without intraperitoneal adhesion. At 20 days after implantation, the volume of collagen of fish scale was significantly reduced; 50 days after implantation, no material was observed by eyes. (4) Pathological examination showed that at 1-3 days after collagen implantation, it was in the stage of acute inflammatory reaction. Cells attached to the material merchant at 5 days. On day 10, vascular structure was formed at the junction of the material and liver. The sinusoid structure of liver was formed in materials at 20-40 days. At 50-60 days, similar hepatic lobule structures could be seen, indicating that the degradation of the material was completed and liver regeneration was basically completed. (5) The results of biological test showed that the hemolysis, epidermal irritation, intradermal irritation, heat source and acute toxicity of collagen of fish scale met the requirements of GB/T16886 Biological Evaluation of Medical Devices. (6) It is concluded that the fish scale collagen extracted by chemical decalcification combined with low temperature enzymatic method has a definite hemostatic effect on bleeding in vivo and on body surface. In vivo degradation time is about 50 days, can provide support for liver regeneration, and is conducive to liver repair.  

Key words: fish scale collagen, biological hemostatic materials, hepatic hemorrhage model, tail hemorrhage model, hemostasis time, bleeding volume, degradation in vivo, liver repair, biocompatibility, absorbable material