Immunization And Histomorphology Study Of Novel Porous Tantalum Implanted Into Muscle

Objective To authenticate the immune reaction and histomorphological circumstance of porous tantalum which were implanted into rabbits , so as to provide the experimental strategies for the clinical application of this material.Methods Porous tantalum were inserted into the right sacrospinal muscle of thirty-two Japanese albino rabbits. Then the animals were divided into four groups in random and executed at 2 ,4 ,8 weeks and 12weeks postoperatively. 1. General observation include the activity of rabbit and information of wound healing.2. Total animals were abstracted venous blood at 1 day preoperatively and before executing. Determine the contents and ratios of CD4+andCD8+ by the test of enzyme linked immunosorbent assay.3. The material and about 1cm surrounding muscle tissue were cut at once after the animals were executed in each group . Observation was carried out as follow : General observation: The adhesive circumstance between material and surrounding muscle was evaluated. Histomorphological observation: The examples were divided into two groups in random and there were four specimens in each group. The materials were extracted from muscle tissue and carried out observation as follow : a) About 0.5mm3 surrounding muscle tissue were cut and made pathological sections after ordinary HE dyeing. Then the sections were observed by light microscope. b) The superficial ultrastructure of Porous tantalum was observed by scanning electron microscope after the materials were freeze fractured by liquid nitrogen. c) The other four specimens were prepared for hard histological section. The sections were observed by light microscope after ponceau dyeing.Results 1. General observation: The food intake and action of animals were normal. Tissular edema, congestion and abnormal excretion were not found .The adherence of muscle and material were compacted.2. The test of enzyme linked immunosorbent assay showed that there was no significant difference in the concentration and ratios of CD4+andCD8+ between experimental group and control group(P>0.05).3. Histomorphological observation: a) Muscle tissue were observed by light microscope: A small quantity of inflammatory cell could be found at the interface between material and muscle at the 2weeks postoperatively. Collagenoblast accrementition ,small amounts neogenetic capillary and hyperplastic fabric capsule wall also could be seen. The amounts of lymphocytes at the 4weeks postoperatively were lesser than 2weeks. Collagenoblast accrementition and fabric capsule wall still could be seen. Lymphocytes were disappeared and fabric capsule wall become thin at the 8weeks postoperatively.Fabric capsule wall were thinner than before at the 8weeks postoperatively. The muscle tissue maintained common physiological structure and shape. b) Porous tantalum materials were observed by scanning electron microscope: Muscle fibers and neogenetic fibrous tissue could cohere on the surface of the material and could grow into the pores of the material with the collagen fibers. With the time increased, muscle tissue could cover the surface of materials. c)Observation of hard histological section: The basal part of interface between muscle and material was covered by fabric capsule wall. Small quantity of fibers and Small vessels could grow into the pores of the material. phagocytic cell, foreign body giant cells and inflammatory cells could not be seen. Material and muscle combined together closely.Conclusion 1. The porous tantalum material and muscle combined together closely after implanting . Hyperergic and inflammatory reaction are not occurrent .So it has satisfactory histocompatibility.2. T- lymph corpuscles subgroup had no significant change after porous tantalum were implanted into muscle. Porous tantalum material dose not cause immunologic rejection and have cytotoxicity. So it is an ideal mounting material for tissue engineering.