BACKGROUNDMicrofracture is a type of bone marrow stimulation in arthroscopic cartilage repair. However, the overall concentration of the mesenchymal stem cells is quite low and declines with age, and in the end the lesion is filled by fibrocartilage. The aim of this research was to investigate a novel method of enhancing microfracture by determining whether low-energy shock waves in microfracture holes would facilitate cartilage repair in a rabbit model.

METHODSFull-thickness cartilage defects were created at the medial femoral condyle of 36 mature New Zealand white rabbits without penetrating subchondral bone. The rabbits were randomly divided into three groups. In experimental group A, low-energy shock-wave therapy was performed in microfracture holes (diameter, 1 mm) at an energy flux density (EFD) of 0.095 mJ/mm² and 200 impulses by DolorClast Master (Electro Medical Systems SA, Switzerland) microprobe (diameter, 0.8 mm). In experimental group B, microfracture was performed alone. The untreated rabbits served as a control group. At 4, 8, and 12 weeks after the operations, repair tissues at the defects were analyzed stereologically, histologically, and immunohistochemically.

RESULTSThe defects were filled gradually with repair tissues in experimental groups A and B, and no repair tissues had formed in the control group at 12 weeks. Repair tissues in experimental group A contained more chondrocytes, proteoglycans, and collagen type II than those in experimental group B. In experimental group B, fibrous tissues had formed at the defects at 8 and 12 weeks. Histological analysis of experimental group A showed a better Wakitani score (P < 0.05) than in experimental group B at 8 and 12 weeks after the operation.

CONCLUSIONSIn the repair of full-thickness articular cartilage defects in rabbits, low-energy shock waves in microfracture holes facilitated the production of hyaline-like cartilage repair tissues more than microfracture alone. This model demonstrates a new method of improving microfracture and applying shock waves in vivo. However, longer-term outcomes require further study.

Animals ; Cartilage, Articular ; injuries ; radiation effects ; Female ; Male ; Rabbits ; Radiation, Nonionizing ; Random Allocation ; Wound Healing ; radiation effects

OBJECTIVETo observe the injury and repair of the subepithelial cordectomy by CO2 laser in different power.

METHODSThirty dogs were randomly divided into 5 groups according to different laser power such as A(1 W), B(3 W), C(5 W), D(8 W), E(cold instruments), 6 dogs in each group. Subepithelial cordectomy was performed on the dogs and the tissue damage and wound recovery were observed in different time after operation.

RESULTSThe mucosa reaction in group C, D was heavier than those in group A, B, E, and the wounds healed slowly with visible pathological scars. The densities of fibroblast and blood capillary were determined with optical microscope. It was found that those in group C, D were higher than those in group A, B, E. The difference was statistically significant (average P < 0.05). Observation by electron microscope showed that the injuries were lighter in group A, B, E and there was no significant difference in vocal cord repair process, while the injuries were more serious in group C, D with few elastic fibers in lamina propria and collagen fibers increased significantly after vocal cord repairing.

CONCLUSIONSThe tissue repair after subepithelial cordectomy by CO2 laser with low power (1 - 3 W) was similar to that by cold instrument surgery.

Animals ; Dogs ; Lasers, Gas ; adverse effects ; Vocal Cords ; pathology ; radiation effects ; Wound Healing

Because no report has been issued on the healing effects of low-intensity pulsed ultrasound on moderate to large fracture gaps, we performed an experimental study using acanineulna full-defect model. Ten mongrel male dogs were divided into two groups: a small defect group and large defect group. The defects were made on the middle one third of both ulnae and one side only was randomly selected for ultrasound sonication, at 1 MHz, 200 microsecond bursting sine wave in 50 mW/cm2 spacial average and temporal average. Sonication was started on the day after surgery and applied for 15 minutes once a day for six days a week. In the small defect group, the means of the radiologic scores, as described by Lane and Sandhu, were 0.6, 4.4, and 8.4 in the control side and 1.8, 6.0, and 10.4 in the treatment side one, three, and five months after the operation, respectively (p=0.0372). In the large defect model, the corresponding means were 2.2, 3.4, and 6.0 in the control side and 3.3, 5.4, and 9.2 in the treatment side (p= 0.009). Low-intensity pulsed ultrasound enhanced new bone formation in small and large full-defects and decreased the incidence of nonunion in the large defect model.
Animal ; Dogs ; Fractures/*physiopathology/*therapy ; Male ; Ulna/*injuries/*physiopathology ; Ultrasonic Therapy/*methods ; Wound Healing/*radiation effects

Remarkable improvement in control of malignant tumor was achieved by combined surgery and postoperative radiation therapy. In Past, radiation therapy had been recommended after 4-6 weeks from operation because of worry about increased complication rate of surgical wound by post-operative irradiation. Nowadays, early surgical extirpation and early post-operative irradiation is recommended for better therapeutic effect. To evaluate the relationship between surgery-radiation interval and healing of surgical wound, an experimental study was undertaken using a total of 132 mice. A single dose of 2000 rads irradiation was delivered immediate after and on 1,3,5,10,14days after incision and suture on the skin of hind limbs of mice. Tensile strengths of the wounds were measured after removal of stitches on 1st, 3rd, 5th, 7th, 10th, 14th and 21st post-operative days. The results are summarized as follows; 1. Wound healing was delayed by irradiation delivered within 3 days from operation. 2. No significant delay of wound healing was observed by irradiation on 5 or more days after operation. 3. Normal wound strength was attained at 21st post-operative day in any surgery-radiation interval. 4. More severe delay of wound healing by irradiation at 24 hrs after operation than by immediate post-operative irradiation although statistical significance is not confirmed. In conclusion, early post-operative irradiation delays healing of the surgical wound though ultimately tensile strength reaches the value of non-irradiated wound.
Animals ; Extremities ; Mice ; Radiation Effects ; Skin ; Sutures ; Tensile Strength ; Wound Healing ; Wounds and Injuries

OBJECTIVETo study the effects of dosages of total body irradiation on the healing process of cutaneous wounds and to observe the changes of wound area at different periods after injury.

METHODSThe entire body irradiation from a (60)Co gamma-ray source was performed on Wistar rats. The single dosage varied from 1 to 8 Gy. Within 1 h after irradiation, two whole thickness circular cutaneous wounds corresponding to 2.5% of total body surface area (Phi = 22 mm) were produced on the back of the animals (combined injury groups). Same wounds were produced on rats with no irradiation (single wound group). Wound healing was observed at different points after injury.

RESULTSAfter total body irradiation with the dose of 1, 2, 3, 4, 5, 6, 7 or 8 Gy, the wound healing was obviously retarded as the dosages increased. The wound area remained was larger in the large dosage groups than in the small dosage groups. Seven days after injury, there was 33.5% wound surface left unhealed in the single wound group, whereas in the combined injury groups, 35.4%, 38.1%, 41.6%, 48.8%, 53.9%, 63.7%, 69.2% and 73.9% of the wound surfaces remained unhealed, respectively. Statistical analysis showed marked correlations between the various times after total body irradiation and various dosages to the percentage of unhealed wound surface. Nine dose-effect relation formulae were deduced according to the statistical results.

CONCLUSIONSIn soft tissue trauma combined with radiation injury, the delay of wound healing is related to the dose of radiation inflicted. It is also related to the time between injury and time of observation.

Animals ; Dose-Response Relationship, Radiation ; Female ; Male ; Rats ; Rats, Wistar ; Time Factors ; Whole-Body Irradiation ; Wound Healing ; radiation effects

OBJECTIVETo investigate the effect of static magnetic field on deep wound healing of SD rats and VEGF during the wound healing and different strength static magnetic field on deep wound healing of SD rats.

METHODSDivided forty-eight SD rats into three groups: 0.16 T magnetic disk treatment (0.16 T group), 0.32 T magnetic disk treatment (0.32 T group), control group. General wounds healing situation was observated on the 3, 6, 9, 12 day. The area of every wound was calculated. The tissue of granulation was dyeing by immune tissue chemical decoration method, in which VEGF protein content with its range in tissue was measured.

RESULTSThe healing index of 0.16 T magnetic group wounds were larger than that of control group on 6th and 9th day, there were statistical difference. The healing index of 0.32 T magnetic group wounds were larger than that of control group on 3rd, 6th, 9th and 12th day, there were statistical difference. The healing index of 0.32 T group wounds contrasted to that of 0.16 T group wounds had no statistical significance. Observation of VEGF at the course of wound healing:the expressing of VEGF in magnetic group wounds on 3rd and 6th was stronger than in control group wounds, there were statistical difference. While there were no obvious difference between them on 9th and 12th day (P>0.05). But the contrast between that in 0.32 T group and in 0.16 T group had no statistical difference. The expressing strength of VEGF in magnetic group reached the peak amplitude on the 6th day, and that in control group reached peak amplitude on 9th day. And the peak amplitude of magnetic group was stronger than that of control group.

CONCLUSIONStatic magnetic disc of 0.16T and 0.32 T can promote deep wound of SD rats heal. The mechanism of static magnetic field promoting wound heal may be relative to the expressing highly of VEGF during early and middle time.

Animals ; Magnetic Field Therapy ; Male ; Rats ; Rats, Sprague-Dawley ; Regeneration ; physiology ; radiation effects ; Skin ; radiation effects ; Vascular Endothelial Growth Factor A ; genetics ; metabolism ; Wound Healing ; radiation effects

3T3 Cells ; Animals ; Cell Membrane ; metabolism ; Mice ; Patch-Clamp Techniques ; Potassium Channels, Calcium-Activated ; radiation effects ; Radiation, Ionizing ; Wound Healing ; radiation effects

Wound combined with total body irradiation (TBI) injury results in impairment of tissue repair and delayed processes of healing, so it has been considered as an important and representative model of impaired wound healing, but the mechanism is not fully clarified. Fibroblasts in wound are the most important cells participating in tissue repair, whereas its radiosensitivity is not high. To understand whether TBI injury has direct damaging effects on fibroblasts in wound, fibroblasts in wound combined with TBI injury and in wound of simple incision injury were isolated and cultured, and parameters associated with tissue repair were determined. The results showed that the abilities of proliferation, attachment and adhesion of fibroblasts isolated from wounds combined with TBI injury significantly decreased as compared with those of simple incision injury, nevertheless, apoptotic ratio of fibroblasts isolated from wounds combined with TBI injury increased significantly. These data suggest that TBI injury may cause direct damaging effects on fibroblasts in wounds, which might be one of the dominant reasons for impairment of wound healing when it is combined with TBI injury.
Animals ; Disease Models, Animal ; Fibroblasts ; metabolism ; physiology ; radiation effects ; Radiation Injuries, Experimental ; metabolism ; Rats ; Rats, Wistar ; Skin ; injuries ; Whole-Body Irradiation ; Wound Healing ; physiology

Animals ; Leukocyte Count ; Leukocytes ; drug effects ; Male ; Mice ; Nerve Growth Factor ; pharmacology ; Skin ; pathology ; radiation effects ; Survival Rate ; Whole-Body Irradiation ; adverse effects ; mortality ; Wound Healing ; drug effects

OBJECTIVETo study the relationship between the expression of Bax, Bcl-2 proteins, and apoptosis in radiation compound wound healing of rats.

METHODSApoptosis, Bax and Bcl-2 proteins were estimated by in situ terminal labeling (TUNEL) and immunohistochemical methods.

RESULTS(1) Changes of the apoptosis in wound healing showed three typical characteristics: early occurrence, high frequency and delayed disappearance after radiation to rats when compared with those of simple wound group, which might be an important reason for radiation-induced delayed wound healing. (2) The expression of Bax protein increased evidently with the increment of apoptosis and showed a good corresponding relationship with the apoptotic frequency in the process of wound healing. While the expression of Bcl-2 protein decreased obviously as the apoptosis reached a maximum and showed increasing tendency up to normal level when the apoptosis decreased distinctively.

CONCLUSIONSBax and Bcl-2 proteins play an important role in the apoptotic regulation of radiation compound wound healing in rats.

Animals ; Apoptosis ; radiation effects ; Female ; Gamma Rays ; Immunohistochemistry ; Proto-Oncogene Proteins ; biosynthesis ; genetics ; Proto-Oncogene Proteins c-bcl-2 ; biosynthesis ; genetics ; Rats ; Rats, Wistar ; Skin ; pathology ; radiation effects ; Wound Healing ; genetics ; radiation effects ; bcl-2-Associated X Protein