Objective To investigate the effects and mechanism of doxorubicin preconditioning in providing ischemic tolerance for rats abdomen island flaps. Methods Twenty-four healthy adult Sprague Dawley rats, 12 males and 12 females, were randomly divided into 3 groups (n=8): control group (group A), ischemic preconditioning group (group B), and doxorubicin preconditioning group (group C). After the abdomen island flap (6 cm × 3 cm in size) based on the superficial inferior epigastric neurovascular bundle was prepared, group A had no further treatment; group B was given a 10-minute ischemia followed by a 10-minute reperfusion for 4 times; and group C was given pretreatment with doxorubicin (1 mg/kg) by injection of the inferior epigastric vein. After 24 hours, the inferior epigastric vessels were blocked by vascular clamp for 4 hours, followed by reperfusion 2 hours to prepare ischemia/reperfusion (I/R) injury model. The rat survival was observed after operation; at 0, 8, 12, 24, and 30 hours after I/R injury, the malonyldiadehyde (MDA) and superoxide dismutase (SOD) levels were measured. At 7 days after I/R injury, the survival rate of flap were calculated and the flaps were harvested for histological observation. Results During experiment, 5 rats died (1 rat in groups A and B respectively, 3 rats in group C) and were added. The survival rates of the flap in group A (10.10% ± 0.43%) was lower than those in group B (91.63% ± 1.76%) and in group C (92.75% ± 1.48%) at 7 days after I/R injury, showing significant differences (P lt; 0.05), and there was no significant difference between groups B and C (t=0.29, P=0.77). Significant difference was found in MDA level and SOD level between group A and groups B, C after 8 hours (P lt; 0.05), and there was no significant difference between groups B and C (P gt; 0.05). Histological observation showed that inflammatory cells infiltration was more obvious and hyperplasia of fibers was weaker in group A than in groups B and C. Conclusion Doxorubicin preconditioning can provide ischemic tolerance for rats abdomen island flaps and protect flaps from the I/R injury. The possible mechanism may be related to that doxorubicin can induce endogenous protections.
Objective To investigate the role of composite graphene-protein hydrogels in repairing spinal cord injury (SCI) and promoting neural regeneration in rats. MethodsA composite graphene-protein hydrogel was prepared using the radical copolymerization method. Its physical properties, including adhesion, were evaluated through shear testing, and cytotoxicity was assessed using the MTT assay. Twenty-four adult female Sprague-Dawley rats were randomly divided into four groups: sham surgery, injury, hydrogel, and hydrogel+graphene groups (6 rats per group). The sham surgery group only exposed the T10 spinal cord tissue. The other three groups underwent laminectomy combined with spinal cord tissue block resection to establish a T10 SCI model. Post-modeling, the hydrogel group and the hydrogel+graphene group received implants of the protein hydrogel and composite graphene-protein hydrogels, respectively, at the injury defect site. The injury group received no additional implant treatment. Postoperative survival rates were monitored across groups. Hindlimb motor function recovery was assessed weekly via Basso-Beattie-Bresnahan (BBB) scores during the 12-week postoperative period. At 12 weeks, motor-evoked potentials were measured to assess neurophysiological function. T10 spinal cord tissue was harvested for histopathological examination via HE staining, followed by immunofluorescence staining for glial fibrillary acidic protein (GFAP), Laminin, and 5-hydroxytryptamine (5-HT) immunofluorescence staining to observe glial scar formation and axonal regeneration at the injury site. ResultsShear testing and MTT assays demonstrated that the composite graphene-protein hydrogels exhibited excellent underwater adhesion and biocompatibility. All rats in each group survived until the end of the experiment. During 12-week postoperative period, the BBB scores in the hydrogel and hydrogel+graphene groups showed a sustained upward trend over time (P<0.05). At 12 weeks after operation, BBB scores were significantly higher in the hydrogel and hydrogel+graphene groups than in the injury group, in the hydrogel+graphene group than in the hydrogel group, showing significant differences between groups (P<0.05). Neurophysiological testing revealed that the motor evoked potential amplitude in the hydrogel+graphene group was significantly higher than that in the injury group and the hydrogel group (P<0.05), with no significant difference compared to the sham surgery group (P>0.05). HE staining revealed that the hydrogel+graphene group exhibited spinal cord morphology most similar to the sham surgery group, with significantly restored tissue structural integrity and minimal vacuolation and inflammatory cell infiltration. Quantitative immunofluorescence analysis revealed that the relative fluorescence intensity of GFAP and Laminin in the injury group was significantly higher than that in the other groups (P<0.05). The relative fluorescence intensity of GFAP and Laminin in the hydrogel+graphene group was significantly lower than that in the hydrogel group (P<0.05). The relative fluorescence intensity of 5-HT in the injury group was significantly lower than that in the other groups (P<0.05). The relative fluorescence intensity of 5-HT in the hydrogel+graphene group was significantly higher than that in the hydrogel group (P<0.05), with no significant difference compared to the sham surgery group (P>0.05). ConclusionThe composite graphene-protein hydrogels effectively repairs SCI in rats by significantly inhibiting glial scar formation at the injury site, promoting 5-HT-positive axonal regeneration, and improving post-injury neurophysiological function and hindlimb motor recovery. It represents a spinal cord repair material with potential clinical application value.
Objective To seek for a method of constructing the tissue microarray which contains keloid, skin around keloid, and normal skin. Methods The specimens were gained from patients of voluntary donation between March and May2009, including the tissues of keloid (27 cases), skin around keloid (13 cases), and normal skin (27 cases). The specimens were imbedded by paraffin as donor blocks. The traditional method of constructing the tissue microarray and section were modified according to the histological characteristics of the keloid and skin tissue and the experimental requirement. The tissue cores were drilled from donor blocks and attached securely on the adhesive platform which was prepared. The adhesive platform with tissue cores in situ was placed into an imbedding mold, which then was preheated briefly. Paraffin at approximately 70℃ was injected to fill the mold and then cooled to room temperature. Then HE staining, immunohistochemistry staining were performed and the results were observed by microscope. Results The constructed tissue microarray block contained 67 cores as designed and displayed smooth surface with no crack. All the cores distributed regularly, had no disintegration or manifest shift. HE staining of tissue microarray section showed that all cores had equal thickness, distinct layer, manifest contradistinction, well-defined edge, and consistent with original pathological diagnosis. Immunohistochemistry staining results demonstrated that all cores contained enough tissue dose to apply group comparison. However, in tissue microarray which was made as traditional method, many cores missed and a few cores shifted obviously. Conclusion Applying modified method can successfully construct tissue microarray which is composed of keloid, skin around keloid, and normal skin. This tissue microarray will become an effective tool of researching the pathogenesis of keloid.
ObjectiveTo summarize clinical experience and curative effect in applying three-dimensional mechanical equilibrium concept to cartilage scaffold construction in total auricular reconstruction.MethodsBetween June 2015 and June 2017, ninety-seven microtia patients (102 ears) were treated with total ear reconstruction by using tissue expanders. The patients included 43 males and 54 females and their age ranged from 7 to 45 years with an average of 14 years. There were 92 unilateral cases (45 in left side and 47 in right side) and 5 bilateral ones. There were 89 congenital cases and 8 secondary cases. According to microtia classification criteria, there were 21 cases of type Ⅱ, 67 cases of type Ⅲ, and 9 cases of type Ⅳ. Tissue expander was implanted in the first stage. In the second stage, autogenous cartilage was used to construct scaffolds which were covered by enlarged flap. According to the three-dimensional mechanical equilibrium concept, the stable ear scaffold was supported by the scaffolds base, the junction of helix and inferior crura of antihelix, and helix rim. The reconstructed ears were repaired in the third stage operation.ResultsAll patients had undergone ear reconstruction successfully and all incisions healed well. No infection, subcutaneous effusion, or hemorrhage occurred after operation. All skin flaps, grafts, and ear scaffolds survived completely. All patients received 5- to 17-month follow-up time (mean, 11.3 months) and follow-up time was more than 12 months in 61 cases (64 ears). All reconstructed ears stood upright, and subunits structure and sensory localization of reconstructed ears were clear, and the position, shape, size, and height of bilateral ears were basically symmetrical. Mastoid region scar hyperplasia occurred in 3 patients, which was relieved by anti-scar drugs injection. No scaffolds exposure, absorption, or structural deformation occurred during follow-up period.ConclusionApplication of three-dimensional mechanical equilibrium concept in cartilage scaffold construction can reduce the dosage of costal cartilage, obtain more stable scaffold, and acquire better aesthetic outcomes.