| To study the effects on the body of animals after incorporation of 3H-TdR and its mechanism, the laws of distribution A retention and absorbed dose in blood , thymus, spleen, femur, heart, lung,kidney, liver, brain , spermary , small intestine and muscle were detected by liquid scintillation counter after 3H-TdR was injected into the tail vein of mouse; the process of dynamic incorporation of in the lymphocytic cell nucleus of blood , thymus , spleen and the nucleus of femur was monitored; the absorbed dose in the cell nucleus was estimated; the influence to RNA's synthesizing and cell's survival was observed using the technology of CLSM; A segment of Egr-1 gene was cloned with reverse transcriptase- polymerase chained reaction, the influence to the expression of Egr-1 gene in the spleen cells was observed.The results of dynamic absorption in the organs after incorporation of 3H-TdR showed that 3H-TdR in the peripheral blood was swiftly distributed to other organs and to their peaks in Id, and was scavenged from them quickly, the formulae of incorporation pattern were described as exponential equation. At the first day after injection, 3H-TdR was distributed mostly in spleen, thymus , femur , liver and small intestine according to their activity; 3H-TdR was distributed mostly in blood, kidney, liver, lung, sperma, brain, spleen , small intestine , muscle , thymus and femur in turn on the basis of their absorbed dose. The retention is lower in every organ at thesixteenth day after injection, the sequence of 3H-TdR incorporation amount isspleen, thumus, smallintestine, kidney, liver, lung, femur, spermary, blood; br -ain, heart, muscle -by turn according to absorbed dose, the absorbed dose of spleen and thymus were 9.9 and 8.3 mGy, far higher than others. According to the absorbed dose of organs at different times, divided by general activity, exported corresponding the change-factor of absorbed dose (Gy ?Bq"1 ?g) .The formulae of dynamic retention pattern of the lymphocytic cell nucleus of blood thymus spleen and femur marrow cell after 3H-TdR injection were described as exponential equation. The absorbed doses of single cell nucleus of spleen and the femur marrow were higher than the lymphocytic cell nucleus of blood and thymus .Applying the technology of CLSM, the spleen cells were scanned and analyzed after the coloration of AO and AO plus PI. The results showed that the ratios of RNA/DNA were significantly higher than that in the control group(P<0.01)when the absorbed dose of 3H-TdR varied from 4.42 to 4.82cGy at 24h after injection. When the absorbed dose varied from 2.92 to 7.61cGy, the survival fraction of spleen cells in different time groups was higher than the control, as testified that low-dosage of the tritium ?ray may significantly increase the amount for RNA synthesis (P<0.01)and stimulate the reproduction of spleen cell, raise the survival fraction.A segment of Egr-1 gene was cloned with reverse transcriptase-polymerase chained reaction, the influence to the expression of Egr-1 gene in the spleen cells was observed. The results showed that the expression of Egr-1 gene in the spleen cells differed from that in the control group(P<0.01) when the absorbed dose of 3H-TdR varied from 4.42 to 4.82cGy at 24h after injection. The expression reached to peak when the absorbed dose is 4.61cGy;IVAt 96h, the expression of Egr-1 gene in the spleen cells was still significantly greater than the control group(/><0.01), the expression is highest at 48h. The results showed that the incorporation of 3H-TdR may induce the greater and long-time expression of Egr-1 gene. The results provided experimental basic for future studies on the radiation effects mechanism of 3H-TdR and the clinical gene radiation therapy of tumors.
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