| The tumor suppressor gene p53 induces growth arrest and/or apoptosis in response to DNA damage/hypoxia. Subterranean rodents could tolerance hypoxia, high carbon dioxide and dark environment, what is more, most of them also can be free from tumor, such as the naked mole rat(Heterocephalus glaber) and the blind mole rat(Spalax), who both have a strong feature of tumor suppressor. The study of anti-tumor in subterranean rodents by molecular biology mainly focused on the regulation and the molecular pathways of tumor suppressor gene. p53 gene could induce cell cycle arrest, repair DNA damage or promote apoptosis. Both DNA repair and apoptosis may reduce the damage on important organization of subterranean rodents by hypoxia(such as brain tissue). These two paths are considered as molecular regulation pathway of tumor suppressor in subterranean rodents, which are induced by hypoxia or DNA damage.This study verified the relationship of personality and weight change, the number of apoptosis cell in hippocampal CA1 region, and the expression of tumorsuppressor gene p53 and HIF-1a, by morphological, histology, and molecular biology theology, through comparative Biology, L. mandarinus as object, L. brandtii as control. The study aimed at exploring the mechanism of tumor suppressor in L. mandarinus. The results were as follows:1. effects of weight change by reoxygenation after acut hypoxiaWe used automatic video analysis software Smart 3.0 to determine the personality of 24 L. mandarinus and 24 L. brandtii and choose 24 individuals(12 L. mandarinus, 12 L. brandtii), which the scores between 0.2 and 0.6 as object to be used for the experiment of weight changes by reoxygenation after acute hypoxia. The result of analysis of repeated measurements ANOVA showed, 1) The trend of weight change of L. mandarinus and L. brandtii was similar both in hypoxia group and control group. Briefly, the trend of weight change of LM-HPY, LM-CON, LB-HPY, LB-COM groups was down firstly, then was up(P =0.015). The weight of both rodents was sharply reduced by hypoxia(P =0.038), while, the species(p =0.956) and the inter function between species and hypoxia(P=0.394) was not significant. 2) The relationship between weight change of L. mandarinus and L. brandtii and personality was not significant(L. mandarinus:y = 3.5195x- 11.672, R2 = 0.0373, P =0.71;L. brandtii:y = 0.6768x- 8.3354, R2 = 0.0041, P =0.91). The result showed the personalization scope of animals in the experiment was better, and hypoxia had similar function on the two rodents. So, these rodents could be subjects to be used in following studies, such as physiology and molecular biology.2. effects of expression of p53 and HIF-1α by reoxygenation after acut hypoxiaWe analyzed the data compared with housekeeping gene β-actin, by the relative quantitative method, though extracting total RNA in brain tissue from 18 L. mandarinus and 18 L. brandtii, reversing transcription into c DNA, obtaining sequence, designing primer, primer-verification, multiple sequence alignment, building evolutionary trees, and comparing the expression of HIF-1α and p53. 1) The influenced on the expression of HIF-1α of L. mandarinus and L. brandtii by different reoxygenation was sharply significant(p <0.01). Briefly, the expression of HIF-1α of L. mandarinus and L. brandtii was up firstly, then was down. The species(P =0.898) and the inter function between species and hypoxia(P =0.002) was sharply significant.2) The expression of HIF-1α of L. mandarinus and L. brandtii peaked when the reoxygenation time was 12 h. The time of the higher expression of HIF-1α of L. mandarinus was later than L. brandtii, which showed the brain tissue lacked of oxygen quickly, the expression of HIF-1α on both of rodents peaked when reoxygenation time was 12 h. 3) The influenced on the expression of p53 of L. mandarinus and L. brandtii by different reoxygenation was sharply significant(P <0.01). Briefly, the expression of p53 of L. mandarinus was up firstly, then was down. The expression of p53 peaked when reoxygenation time was 12 h, then reduced. While, the expression of p53 of L. brandtii had no change in the overall. The inter function between species and hypoxia was sharply significant(P <0.01), the species was not significant(p =0.996). 4) The positive relationship between the expression of HIF-1α and p53 was sharply significant(P =0.004), which showed brain in hypoxia could induce the expression of p53.3. effects of CA1 cells in hippocampus by reoxygenation after acut hypoxiaWe used 18 L. mandarinus and 18 L. brandtii as object, by TUNEL staining and microscope, to make paraffin in hippocampus CA1 region and count the number of apoptotic cells under the magnification of 40×10. The result of analysis of two-way ANOVA showed, 1) The influenced on apoptotic cells of hippocampus CA1 region of L. mandarinus and L. brandtii by different reoxygenation was significant(p <0.01). Briefly, the trend of apoptotic cell of L. mandarinus and L. brandtii was up firstly, then was down. The inter function between species and hypoxia was significant(P <0.01), while the species was not significant(P =0.898). 2) The apoptosis index of L. mandarinus peaked when the reoxygenation time was 24 h, while, the AI of L. brandtii peaked when the reoxygenation time was 12 h. The result showed the time of higher AI was later than L. brandtii’s, hypoxia did early influence on L. brandtii, and L. brandtii suffered damage more early. 3)The negtive relationship between the expression of HIF-1α and apoptosis of L. mandarinus was sharply significant(y =-0.295ln(x) + 0.2214, R2 = 0.365, P =0.008), which showed HIF-1α could inhibit apoptosis. While, the positive relationship between the expression of HIF-1α and apoptosis of L. brandtii was sharply significant(y = 0.1503x- 0.0508, R2 = 0.3945, P =0.005), which showed HIF-1α could induce apoptosis. |
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