Objective To discuss the effect of sciatic never repair at different angles on the neural regeneration in rats. Methods Seventy-two male Sprague Dawley rats were randomly divided into groups A, B, C, and D with 18 rats in each group. The right sciatic nerve was transected at 30, 45, 60, and 90° in groups A, B, C, and D, respectively, and then was repaired. The morphologic assessment of nerve regeneration was performed by gross observation, the wet weight recovery rateof gastrocnemius, histological and ultrastructural observations at 1, 2, and 3 months after operation. Results Three months later, the wet weight recovery rate of gastrocnemius, motor nerve conduction velocity and action potential of sciatic nerve, axonal diameter, medullary sheath thickness, and medullated nerve fiber counting in groups A and B were significantly better than those in groups C and D (P lt; 0.01); but no significant difference was found between group A and group B (P gt; 0.05), and between group C and group D (P gt; 0.05). Conclusion End-to-end neurorrhaphy at 30-45° can effectively promote the sciatic nerve regeneration in rats.
Objective To prepare silver-containing hydroxyapatite coating (hydroxyapatite/Ag, HA/Ag) and investigate its antibacterial property and biocompatibil ity in vitro. Methods Vacuum plasma spraying technique was adopted to prepare HA/Ag coating on titanium alloy substrate (3% Ag). After incubating the HA/Ag and the HA coating under staphylococcus aureus and pseudomonas aeruginosa suspensions of 2% tryptic soy broth (TBS) medium for 2, 4 and 7 days, respectively, the biofilm on the coatings was examined by confocal laser scanning microscope, and the bacterial density and viable bacterial percentage of bacterial biofilm were calculated. Meanwhile, the micro-morphology of bacterial biofilm was observed by SEM, the cytotoxicity was detected via MTT and the biocompatibil ity of biofilm was evaluated by acute aemolysis test. Results Compared with HA coating, the bacterial biofilm’s thickness on the surface of HA/Ag coating witnessed no significant difference at 2 days after culture (Pgt; 0.05), but decreased obviously at 4 and 7 days after culture (P lt; 0.01). The bacterial density of the biofilm increased with time, but there was no significant difference between two coatings (P gt; 0.05) at 2, 4 and 7 days after culture. The viable bacterial percentage of the biofilms on the surface of HA/Ag coating decreased obviously compared with that of HA coating at 2, 4 and 7 days after cultureP lt; 0.01). The MTT notified the cytotoxic grade of both coatings was zero. The acute haemolysis assay showed that the hemolytic rate of HA/Ag and HA coating was 0.19% and 0.12%, respectively. Conclusion With good biocompatibil ity, significant antibacterial property against staphylococcus aureus and pseudomonas aeruginosa, no obvious cytotoxicity and no erythrocyte destruction, the vacuum plasma sprayed HA/Ag coating is a promising candidate for the surface of orthopedic metal implants to improve their osseointegration and antibacterial property.