RESUMO
BACKGROUND:In recent years, calcium alginate dressing has been widely used in surgical hemostasis, traumatic hemostasis, postoperative nasal hemostasis and puncture site hemostasis,etc.; however, there are few reports on their hemostatic mechanisms. OBJECTIVE: To preliminarily study the hemostatic mechanism of calcium alginate dressing. METHODS: Human anticoagulant blood was respectively dropped on sodium alginate dressing, nasopore dressing and medical cotton gauze. After 2 minutes, the interaction between materials and blood was observed at the room temperature using scanning electron microscopy. Calcium alginate dressing, nasopore dressing and medical cotton gauze were added in human red blood cel suspensions respectively. After 15 minutes, the interaction between materials and red blood cels was observed using scanning electron microscopy. The red blood cels were suspended by different concentrations (10, 5, 2.5 g/L) of alginate dressing extracts. The erythrocyte sedimentation rate was observed at different time points (30, 60, 120 minutes). Platelets rich plasma was incubated with different concentrations (10, 5, 2.5 g/L) of alginate dressing extract at 37℃, then CD62P positive platelet percentage was measured by flow cytometry after 10 minutes of incubation. RESULTS AND CONCLUSION: Dense fibrin network was formed after calcium alginate dressing contacting with an anticoagulant. A large number of blood cels were recruited. There were only a smal amount of red blood cels and platelets adhesion in the nasopore dressing and medical cotton gauze groups. After the calcium alginate dressing interacting with red blood cels, red blood cel deformability was visible, with a pseudopodia-like change. The red blood cel morphology was unchanged in the nasopore dressing and medical cotton gauze groups. The calcium alginate dressing extract dose-dependently and time-dependently increased the red blood cels aggregation, comparative differences between groups was statisticaly significant(P < 0.01). The calcium alginate dressing extract dose-dependently enhanced the CD62P positive platelet percentage, comparative differences between groups was statisticaly significant (P< 0.01). These results demonstrate that calcium alginate dressing promotes hemostasis and coagulation process by releasing of calcium ions, causing red blood cel aggregation and deformation and activating platelets.
RESUMO
BACKGROUND:Hemostatic dressing can directly contact with the body tissues on the wound surface. The biocompatibility is one of the important indicators of evaluating the advantages and disadvantages of dressing. The hemostatic dressing prepared with calcium alginate as raw material has become a research focus owing to its low cost and good compatibility. OBJECTIVE:To observe the cytotoxicity of calcium alginate hemostatic dressings and to compare the cytotoxicity between calcium alginate hemostatic dressing and gelatin hemostatic sponge, absorbing cotton, ordinary gauze. METHEDS:Leaching solution method: the DMEM high glucose culture solution was taken as the leaching medium. The calcium alginate hemostatic dressing, gelatin hemostatic sponge, absorbing cotton and ordinary gauze leaching solution were respectively prepared. Five concentration gradients of 100%, 75%, 50%, 25%, 50% were set. The fibroblast cels of L-929 mouse were cultured for 24 hours with the above material leaching solution. The volume fraction of 10% DMEM high glucose culture medium was taken as control group, and DMEM high glucose culture medium containing 5% DMSO was taken as positive control group to observe the cel proliferation and morphological changes. Direct contact method: The fibroblast cels of L-929 mouse were respectively seeded in calcium alginate hemostatic dressing, gelatin hemostatic sponge, absorbing cotton and ordinary gauze and cultured for 24 hours. The changes in cel morphology were observed. RESULTS AND CONCLUSION: Leaching solution method: The cytotoxicity of alginate fiber hemostatic dressing, gauze, absorbing cotton leaching solution with different concentration gradients was grade 1, which was in line with GB/T16886/ ISO10993 biological evaluation standard of medical apparatus and instruments. The cytotoxicity of 100%, 75% gelatin hemostatic sponge extract solution was grade 3, causing severe inhibition of cel proliferation. Direct contact method: The cytotoxicity of gauze and alginate fiber hemostatic dressing was grade 1, absorbing cotton was grade 2, gelatin hemostatic sponge was grade 3. These results demonstrate that calcium alginate hemostatic dressing has no cytotoxicity.