Objective To prepare carboxymethyl-chitosan/hyaluronic acid/poly(vinyl alcohol) (CHP) blend membrane, evaluate its physicochemical properties and intraocular biocompatibil ity and to investigate its feasibil ity to be appl ied to glaucoma filtering surgery. Methods CHP blend membrane was prepared using solution casting method after blending carboxymethyl-chitosan, HA and poly(vinyl alcohol) in a proportion of 5 ∶ 4 ∶ 1 (M/M). Its water absorption rate, swell ing rate, permeabil ity, and mechanical properties were detected. Subconjunctival fibroblasts separated from subconjuncitival tissue of New Zealand white rabbits were cultured, and the cells at passage 4 were cultured on cell culture plate with or without the CHP blend membrane, serving as the experimental group and the control group, respectively. Effectof the CHP blend membrane on the subconjunctival fibroblasts was tested by MTT method 24, 48, and 72 hours after culture. Six New Zealand white rabbits were randomly divided into two groups (n=3 rabbits per group), and the CHP blend membrane and SK gel were implanted into the rabbits’ subconjunctival space and anterior chamber in the experimental group and the control group, respectively. Sl it lamp observation and binocular reaction record were conducted 1, 3, 5, 9, 11, 20, 30, 45, and 60 days after operation. Corneal tissue harvested from the experimental group was observed using scanning electron microscope 15 days after operation to study ophthalmic biocompatibil ity and biodegradabil ity. Results The water absorption rate and the swell ing rate of the CHP blend membrane was 83.8% ± 1.3% and 3.59 ± 0.50, respectively. The tensile strength of the dry and the wet CHP blend membrane was (20.59 ± 1.73) and (0.51 ± 0.13) MPa, respectively. The breaking elongation rate of the dry and the wet CHP blend membcane was 10.69% ± 1.16% and 53.15% ± 2.46%, respectively. The CHP blend membrane had good permeabil ity to NaCl and L-tyrosine. Absorbance (A) value of the experimental group 24, 48, and 72 hours after breeding was 0.207 ± 0.083, 0.174 ± 0.080, and 0.181 ± 0.048, respectively, while the A value of the control group was 0.284 ± 0.011, 0.272 ± 0.083, and 0.307 ± 0.056, respectively. Significant difference was evident between two groups (P lt; 0.05). In the experimental group, a small amount of floccus was exuded around the implanted membrane 1 day after operation; the floccus was absorbed on the third day, and there was no obvious inflammatory reaction occurring on the eleventh day. Most of the membrane degraded on the sixtieth day. Scanning electron microscope observation showed that the hexagonal morphology of the corneal endothel ial cells was intact, and no degradation particles adhered to the surface. In the control group, the implantation of SK gel into anterior chamber was unsuccessful because the SK gel was quite soft and easily broken. In the experimental group, mild hyperemia emerged around the implanted membrane 1 day after the subconjunctival implantation of the membrane, and it became normal on the ninth day. No corneal edema and inflammatory reaction of anterior chamber occurred till the sixtieth day. The results in the control group and the experiment group were similar. Conclusion Due to its good physicochemical properties and biocompatibil ity, the CHP blend membrane has potential appl ications in glaucomafiltering surgery.
Objective To study hemostasis of a new chitosan hemostatic powder. Methods Twenty-four adult SD rats were made the models of l iver injury, male or female, and weighing 210-240 g. They were divided into three groups randomly (n=8) depending on different hemostatic powders. The incision of the l iver was treated with 300 mg Yunnan baiyao (group A1), chitosan hemostatic powder of pH6.5 (group B1) and pH7.5 (group C1), respectively. The bleeding time and bleeding amount were recorded. In vitro, with the modified Ree-White method, 2 mL artery blood from New Zealand whiterabbit was added into the 0.2 mL solution of Yunnan baiyao, chitosan hemostatic powder of pH6.5 and pH7.5 (concentration of 0.2 mg/mL), respectively. The blood coagulation time was recorded. The chitosan blood clots of group B2 and group C2 were observed with scanning electron microscopy (SEM). Results The bleeding time of group A1, group B1 and group C1 was (292 ± 31), (261 ± 23), and (224 ± 28) s, respectively, the bleeding amount was (1.63 ± 0.21), (1.47 ± 0.18), and (1.18 ± 0.17) g, respectively, showing statistically significant differences between groups B1, C1, and group A1 (P lt; 0.05), between group C1 and group B1 (P lt; 0.05). The blood clotting time of group A2, group B2, and group C2 was (653 ± 41), (255 ± 20), and (202 ± 11) s, respectively, showing statistically significant differences between groups B2, C2, and group A2 (P lt; 0.05), between group C2 and group B2 (P lt; 0.05). The SEM showed that the blood cells of group B2 and group C2 gathered around the chitosan. Conclusion Chitosan hemostatic powder of pH7.5 has good hemostasis.