ABSTRACT
Objective To study the role of the oxidative stress in the development of wound healing and observe the effect of the antioxidant PTD-SOD on damage and inflammation reaction after mechanical wound. Methods In this experiment,acute wound healing model by removal the whole layer dorsal skin of the mice was prepared,SOD(3 000 U and 6 000 U)and the fusion protein PTD-SOD with different concentrations(1 000 U,3 000 U,6 000 U and 10 000 U)were used to deal with the wounds continuously for 13 days.The mice were divided into different concentration SOD treatment group and PTD-SOD treatment group,model control group,physiological saline treatment group and compound iodine solution control group.The wound healing situation and healing percentage of the fight and left skin wounds of each mouse in every group was recorded every day.At day 14 after wound,the wound healing skin of each group was removed and some were used to make 10%tissues homogenate for detecting the activities of superoxide dismutase(SOD),catalase(CAT),glutathione peroxidase(GSH-Px)and contents of malondialdehyde(MDA)and hydroxyproline(Hyp);in the meantime,the other removed skin were fixed in 10% formalin for observing the histopathological changes of the tissues. Results Compared with the model control group,the physiological saline treatment group and the compound iodine solution control group,the skin wound healing percentage was significantly(P<0.05 or P<0.01)improved,with increase of the activities of SOD,CAT,GSH-Px and contents of Hyp (P<0.05 or P<0.01)and decrease of MDA(P<0.05 or P<0.01) in the SOD groups or PTD-SOD groups (except for 10 000 U PTD-SOD group).When compared with the physiological saline treatment group or the compound iodine solution treatment group,the effect was similar to the model control group.In comparison to the SOD groups,under the same dosage and environment condition,the PTD-SOD groups were much better than SOD groups with regard to promoting skin wound healing percentage,increasing activities of antioxidases and contents of Hyp,decreasing contents of MDA.Among the PTD-SOD groups,the effect of high dosage 10 000 U on promoting skin wound healing was declined. Conclusions The oxidative stress may playan important role in the development of wound healing.Proper application of treatment with antioxidants is a alternative strategy in the early stage of wound.PTD-SOD is able to prevent the oxidative stress damage,inhibit inflammatory infiltration and promote skin wound healing efficiently.
ABSTRACT
BACKGROUND:Biocompatibility is a key parameter in drug delivery systems. In general, to obtain a proper microparticle carrier, the materials themselves should have excellent biocompatibility. Besides, spherical degree and surface smoothness both have significant influence on biocompatibility.OBJECTIVE: To obtain spherical and smooth poly (lactide-co-glycolide)microparticles, so as to improve the property of biocompatibility.DESIGN: Open experiment.SETTING: Research Laboratory of Biomaterials, Jinan University.MATERIALS: The experiment was conducted in the Research Laboratory of Biomaterials, Jinan University, between June 2004 and January 2005.The materials included poly(lactide-co-glycolide), lysozyme and poly (vinyl alcohol). The other reagents were analytical pure. The instruments included a homogenizer, a mechanical stirrer, an ultrasonic cleaning instrument, a scanning electron microscope and an atomic force microscope.METHODS: ① Preparation of microparticles: Lysozyme was selected as a model protein for encapsulation into poly(lactide-co-glycolide) using a dou-ble emulsion solvent extraction/evaporation method. Three separation methods, namely direct vacuum freeze-drying, filtration and centrifugation,were investigated and compared. ② Observation under the scanning electron microscope: We observed the effect of three separation methods on the shape of microparticles. All the samples were attached to copper mounts and coated with gold, and then were observed with an electron microscope.③ Observation under the atomic force microscope: The morphological structure of the surface was analyzed with atomic force microscope.RESULTS: ① Observation results of scanning electron microscope: Compared with direct vacuum freeze-drying and filtration, centrifugation method was more efficacious in obtaining spherical and smooth microparticles based on the scanning electron microscope pictures. But results also warned us to be more careful when we prepared scanning electron microscope samples using ultrasonic to separate the aggregates. ② Atomic force microscope results indicated that the surface was smooth with the average roughness of 48.55 nm.CONCLUSION: By investigating the influence of different downstream processes, we can obtain spherical and smooth products. Besides, a new one-step method is put forward in constructing some microparticle-combined polymer based scaffolds because the combined scaffolds and microparticles are formed synchronously.