OBJECTIVE To investigate the effect of meniscus suture on meniscus healing which included healing time and healing pattern. METHODS Fourty healthy rabbits were adopted in this study. The model of meniscus injury was made by a longitudinal incision at the medial meniscus of the left knee. The rabbits were divided into two groups, the experimental group was treated by meniscus suture and the control group was unsutured. After operation, the meniscus samples were collected periodically and observed by gross, light and electronic microscope to analysis the meniscus healing. RESULTS The injured meniscus was healed gradually and completely at the sixth week in the experimental groups. More fibroblasts and less fibrocartilage cells could be observed in the healed meniscus. Oppositely, there was no meniscus healing in the control group and the edge of injured meniscus was sealed by epithelioid cells. CONCLUSION The meniscus suture can accelerate the healing process of meniscus injury. Besides, early suture make the injured meniscus correctly positioned to ensure the normal healing process.
Application of the island flap on the back of rabbit as a model, the central vessel and its anterior edge vein was perserved. We explored the features of the blood supply and the difference in the dependence of the recipient bed of pure venous flap, arteriolised venous flap and conventional flap. The result showed that the conventional flap and arteriloized venous flap could survive, but the pure venous flap could not. It was suggested that the pure venous flap was in an impending necrotic condition, therefore,the blood circulation of recipient bed and the rate of revascularization between the recipient bed and the flap seemed to play an important role in the survival of the flap.
Hyaluronic acid (HA) is an extracellular matrix having a high molecular weight. This study is to investigate (1) whether the ultrapure HA had effect on the healing of full thickness skin wounds in animals, and (2) the relation between the effect of HA and the size of the molecular weight of HA. The ultrapure HA with different molecular weights and HA with intermediate molecular weight were applied topically to the wounds from removal of full thickness of skin and topical application of normal saline was used as control. At 21st, day after the topical application, the tensile strength was reduced in wounds of groups of HA with high and intermediate molecular weights, but not in the group of low molecular weight. Using laser-Doppler scanning of the dynamic changes of the wound perfusion, in the 3rd day the blood supply to the wound was reduced in HA groups of high and intermediate molecular weights, but at the 7th day, the blood supply of all wounds in the two groups was increased. The study revealed that HA with different molecular weights had different actions on the contraction of wounds, the angiogenesis of the granulation tissues and the healing strength of the wounds. It was indicated that hyaluronan could be used for wound treatment or as a carrier, but its accurate composition must be carefully noted.
Local hypothermia as a preventive method to reperfusion injury of skeletal muscles was studied. Sixteen Japanese rabbits were divided into four groups at random. Before the tourniquet was inflated, a cold gel pack was applied to the right hind leg of each rabbit for 15 minutes to produce local hypothermic condition, without application of tourniquet the left hind limb was under local hypothermic condition as a control. The duration of tourniquet ischemia was 4 hours, and then reperfusion for one and two hours in the A and B groups respectively; in the C and D groups the duration of ischemia was 5 hours, and reperfusion for one and two hours, respectively. The muscle temperature averaged 16.6 degrees C with a needle thermocouple in the hind limb under local hypothermia. The serum K+, LA, SOD, LPO were determined from bilateral femoral veins, and electron and light microscopic studies of sural muscles were done in the post-reperfusion period. It was found that the K+, LA, LPO were lower than that of the control groups (P lt; 0.01), but SOD was higher than that of the control group (P lt; 0.01). Electron and light microscopic studies showed sight but reversible damage of muscular structure with the possibility of in the hypothermic groups cell regeneration. Basing on this experimental results, this method was applied in 45 cases reparative and reconstructive surgery of limbs. The duration of application of tourniquet averaged 2 hours and 57 minutes, the longest being 4 hours and 31 minutes, when the muscle temperature had reduced to 22.4 degrees C. There were no postoperative complications associated with this technique. Local hypothermia appeared to be a safe and effective method of decreasing the reperfusion damage after ischemia.
Abstract A new kind of soft tissue expander with exteriorized injection valve was reported. Two types of expanders were designed: one with single cyst, single tube and single chamber, and the other with single cyst, single tube but double chambers, i.e, an additional drainage chamber. The drainage orifice could be controlled by a valve. An animal experiment had been conducted, and the outcome suggested that the new expander could provide rapid expansion of the soft tissue, sufficient drainage of the expanded area. The bacterial culture showed that among the 42 samples obtained from the expanded cyst, only 3 were positive. (2 of bacteria and 1 of fungus), suggesting comparatively low cyst infection.
In order to investigate the possibility of porous hydroxyapatite ceramics (HAC) in the repair of skull bone defect, twenty-four rabbits were used. The bone defect model was created by operation to obtain a defect in parietal bone in a size of 1 cm x 1 cm. Filled the defect with HAC and methyl-methacrylate-syrene copolymer (MMAS) to fill the defect as control. At 1st, 2nd and 3rd months after operation, behavior of the rabbits was observed and then these animals were sacrificed and specimens were examined under microscope. Results showed as follows: after operation, behavior of all animals were normal. By histological examination, it was found that in HAC group, there were granulation tissue, fibrous tissue and newly formed vessels grew into the pores and the osteoblasts formed osseous trabeculae. There was no inflammatory cell infiltration. In the MMAS grafted asea, there was formation of fibrous membrane. It suggested that HAC might be a good material for bone substitute in repair of skull bone defect.
This experiment consisted of removing a segment of femoral artery measuring 3cm from Japanese white rabbits. The arterial segments were divided into 3 groups and grafted as homograft at different periods of time. The segments in group 1 were grafted immediatly after their removals, those in the group 2 and group 3 were stored at -30 and -196 degrees centigrade before grafting, respectively. The results from gross and histological examinations, it was noted that following deep freezing the long term patency rate after grafting of the arterial homografts was superior to those not undergoing deep freezing. Those stored at 30 degrees centigrade for 12 weeks had the lowest patency rate.
The experiment was earied out on the a boomen of the whiterats. The epigastric vein wasarterialized by means of anastomcois with the femoral artery, lateral thoracic vein was reserved as aefferent vessel. The changes of hemorheology were mesured after arterialization, and were comparedwith the changes in the normal A-V skin flaps. The levels of platelet, aggreation, blood viscosityand plasma fibrinogen in arterialized vein flape were signmeantly higher than that in A-V flaps. ASa r...
The aim of this experiment was to study the osteogenesis in vivo of allogenic osteoblast combined culture with calcium phosphate composites. The osteoblasts were obtained by enzymatic digestion of periosteum from fibula subcultured to 13 generations, the cells were combined culture with hydroxyapatite and biphasic calcium phosphate. Subseguently, the composite was implanted into rabbits subcutaneously or intramuscularly. The blank material was implanted in the contralateral side as control. Four weeks later, all animals were sacrificed. All the implants were examined by gross observation, histological examination and EDXA. The results showed: 1. obvious ingrowth of connective tissue with very little inflammatory reaction; 2. new bone formation in the composites with deposit of Ca and P on the surface of osteoblast, but none in the blank materials; 3. no significant difference of new bone formation between the different sites of implantation or different materials, but those implanted intramuscularly had lamellae form of new bone while those implanted subcutaneously had only mineralization of extracellular matrix. The conclusion were: 1. the composites are biocompatible with prior osteogenesis property; 2. periosteal-derived allogenic osteoblasts obatined by enzymatic digestion could survive following implantation with bioactivity; 3. rich blood supply might be advantageous to new bone formation and its maturation.
Motor endplate is the structure connected between the nerve terminal and muscle fibre and plays a very important role in conducting nerve impulses to the target, therefore, systemical study of the sequential changes of the motor end-plate upon denervation is quite important.Ninety New Zealand rabbits were divided into nine groups from two weeks to nine months after denervation. Acetycholinesterase(AchE) was analyzed quantitatively to study the sequential changes of the motorendplates of tibialis anterior muscle. The results showed that there was no significant reduction of AchE at theend if one month after denervation, whereas a sharp reduction of AchE afterwards. AchE could not be stained after five month denervation.