The effects of liver tissue factor on the healing of experimental fracture made on the tibia white rats were observed biochemically and histologically. The liver tissue factor was prepared as follows; Sixty normal rat livers were homogenized in Warring Blender. Four parts of distilled water were added to one part of emulsion-like liver homogenate and the mixture was left in the room temperature for several hours. It was then filtered through three layers of fine mesh gauze. The filtrate was centrifuged in a model PRI International Centrifuge with 15000/r.p.m. for 40 minutes under refrigeration. The supernatant was transferred and 1/2 volume of 95% ethyl-alcohol was added and this mixture was stored in a refrigerator for 24 hours or 48 hours. The sediment was centrifuged. The precipitate as a 10% water solution was ready for injection.
In this study healthy adult white rats weighing approximately 200 gm. were used and the animals were divided into the following four experimental groups;
Group 1 :16 rats, control.
Group 2 : 48 rats, fractured but given no liver tissue factor.
Group 3 : 48 rats, fractured and given liver tissue factor.
Group 4 : 32 rats, studied histologicaly.
After the experimental fracture was made-1. ml. to 2 ml. of the liver tissue factor was injected_ intraperitoneally everyday or every other day in group 3 as described in the text. All animals in group 2, 3, and 4 were sacrificed at intervals of 5 to 40 days and healing of the fracture was evaluated by determination of total phosphorus and nucleic acid contents of bones as follows;
Some of the specimens were also studied histologically.
1) Nucleic acid (DNA-P and RNA-P) content in normal rat bone was measured as RNA-P 46.18 . ±2.68 mcg.,/100 mg. DNA-P 9.14±1.07 mcg./100 mg. in the delipitated dry ´powder and RNA/DNA ratio was 4.76±0.28.
2) Phosphorus metabolism revealed more active in the fractured bone than in the normal bone and increased markedly on the 20th post-fracture day. It increased more markedly in the fractured rats receiving the liver tissue factor.
3) In the group 2, the nucleic acid content was higher in the fractured bone than in the unfractured. 4) In the group 3 in which the liver tissue factor was administered, the contents of RNA and DNA were markedly higher in the fractured bone than in the unfractured.
5) In general, the contents of RNA and DNA in the fractured bones were higher than in the unfractured, and were more marked in the group receiving the liver tissue factor.
6) It is assumed that the tissue factor might stimulate the synthesis of DNA in the fractured bone. 7) Microscopic examination demonstrated a slight increase of cell infiltration within the bone tissue in the group receiving the liver tissue factor.
In summary, it seems that the liver tissue factor may stimulate the, healing of fractured bone.
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