人类Y染色体基因多态性研究初探

Y染色体作为人类惟一的父系遗传的染色体,单倍群保存完整并且易于鉴定和使用,在基因多态性的研究中的重要性日益受到人们的关注.本文就Y染色体的遗传特征、现在常用的遗传标记以及在人类学和疾病相关性的应用作一综述.

Abstract：

Y chromosome is the only human chromosome which is paternally inherited. Its haplogroup is almost fully conserved, and is easy to be identified and to be used, which has resulted in more and more academic studies related to Y chromosomes. In this article , we will review its genetic characteristics, genetic markers, and its application in anthropology and association with human diseases.     

氟中毒对大鼠脑组织Ras-Erk1/2通路及转录因子CREB的影响

目的研究慢性氟中毒大鼠脑组织中细胞外信号调节蛋白激酶（Extracellular signal regulated kinases,Ras-Erk1/2）通路主要激酶表达变化及其对转录因子环一磷酸腺苷反应单元结合蛋白（cAMP Responsive Element Binding Protein,CREB）的影响。方法 SD（Sprague dawley）大鼠随机分为3组,即正常组、饮水中小剂量加氟（5 mg/L）组、大剂量加氟（50 mg/L）组,实验期为6个月。实验结束时,用氟离子选择电极法测定大鼠尿氟及血氟含量,尼氏染色检查神经细胞尼氏小体改变,蛋白印迹（Western-blotting）方法检测脑组织中小鸟苷三磷酸结合蛋白（small GTP-binding protein,Ras）、Erk1/2、CREB信号转导激酶的蛋白表达水平,实时荧光定量聚合酶链式反应（Real-time Polymerase Chain Reaction,Re-al-time PCR）方法检测c-fos基因mRNA表达水平。结果与对照组相比,染氟组大鼠有不同程度的氟斑牙及血氟尿氟升高;大脑皮质和海马部位神经细胞尼氏小体减少;脑组织中Ras、phospho-Erk1/2t、otal-Erk1/2及phospho-CREB蛋白表达水平上升（F值分别为19.9、114.59、4.6 9、7.6,P〈0.05）,以大剂量染氟组尤为明显t,otal-CREB在各组间未见明显改变;大剂量染氟组c-fos基因mRNA表达明显升高,而小剂量染氟组该基因mRNA表达降低。结论过多的氟可引起大鼠脑组织神经细胞损伤,脑组织中Ras-Erk1/2信号激酶通路过度激活可刺激转录因子CREB磷酸化,从而影响c-fos基因的表达,该过程可能参与慢性氟中毒脑损伤机制。     

燃煤型氟中毒大鼠脑组织神经型尼古丁受体mRNA及蛋白表达水平改变

目的 观察燃煤型氟中毒大鼠学习记忆能力变化,测定大鼠脑组织神经型尼古丁受体(nAChR)mRNA和蛋白表达水平,探讨大鼠学习记忆能力改变的发生机制.方法 健康SD大鼠24只,体质量100～120 g,按体质量随机分为3组,每组8只.对照组饲以常规饲料,低氟组和高氟组以燃煤型氟中毒重病区燃煤烘烤的当地玉米为主要饲料(含氟量分别为11.30、104.20 mg/kg)来复制慢性氟中毒大鼠模型,染氟时间为6个月.染氟结束后,用Morris水迷宫方法检测大鼠行为学变化,处死动物取脑,用匀浆-氟离子选择电极法测定脑组织含氟量,实时荧光定量PCR法检测nAChR mRNA水平,蛋白印迹法测定nAChR蛋白表达水平.结果 低氟组和高氟组大鼠逃避潜伏期时间[(12.42±8.03)、(17.48±8.05)s]较对照组[(7.04±3.29)s]显著延长(P均<0.05),高氟组第7天穿过平台次数[(1.62±0.87)次]和逗留平台象限时间[(16.70±5.02)s]较对照组[(3.53±1.67)次、(23.33±5.35)s]降低(P均<0.05).低氟组和高氟组大鼠脑组织含氟量[(1.14±0.04)、(1.79±0.04)mg/kg]显著高于对照组[(0.52±0.05)mg/kg,P均<0.05],且高氟组大鼠脑组织含氟量高于低氟组(P<0.05).高氟组大鼠脑组织nAChR α3、α4、α7亚单位mRNA水平(1.51±0.20、1.45±0.06、1.63±0.08)较对照组(1.79±0.11、1.66±0.14、1.83±0.06)显著降低(P均<0.05),而低氟组(1.65±0.17、1.59±0.09、1.71±0.03)与对照组比较无明显改变(P均>0.05).低氟组和高氟组大鼠脑组织nAChR α3、α4、α7亚单位蛋白表达水平(0.58±0.13、0.16±0.03、1.41±0.38和0.56±0.23、0.08±0.02、0.51±0.16)较对照组(1.48±0.42、0.57±0.21、2.56±0.26)显著降低(P<0.05或<0.01).结论 燃煤型氟中毒大鼠学习记忆能力降低可能与脑组织nAChR蛋白表达及mRNA水平降低有关,nAChR表达改变可能是引起动物学习记忆能力降低的主要机制.

Abstract：

Objective To observe the learning and memory changes in coal-burning type of fluorosis rats, detect the expressions of neuronal nicotinic acetylcholine receptor(nAChR) at mRNA and protein levels in rat brains and to reveal the mechanism of changed learning and memory ability. Methods Twenty-four healthy SD rats, weighting 100 - 120 g, were randomly divided into three groups(8 in each). Control group was fed with normal diet, and low- and high-dose fluoride groups were fed with corn polluted with high fluoride (fluoride were 11.30,104.20 mg/kg, respectively) during drying processes with local burning-coal from the areas of endemic fluorosis to established rat model of chronic fluorosis. After exposed to fluoride for 6 months, behavioral changes were measured by Morris water maze. Animals were sacrificed, the brain was taken, after homogenizing the fluoride content of brain tissue was determined by fluoride ion selective electrode. The α3, α4 and α7 nAChR subunits at mRNA and protein levels were analyzed by real-time PCR and Western blotting, respectively. Results For rats in low- and high-fluoride groups, the escape latency time[(12.42 ± 8.03),(17.48 ± 8.05)s] was significantly longer than that in the control[(7.04 ± 3.29)s, all P< 0.05]. For rats in high-fluoride group, the numbers of crossing the platforms (1.62 ± 0.87) and the time of staying at the platforms[(16.70 ± 5.02)s] were significantly decreased as compared to that of control[3.53 ± 1.67, (23.33 ± 5.35)s, all P < 0.05]. The fluoride content in rat brain tissue in low- or high-fluoride groups [(1.14 ± 0.04), (1.79 ± 0.04)mg/kg] was significantly higher than that of control [ (0.52 ± 0.05) mg/kg, all P < 0.05]; in addition, the amount of fluoride in brain tissue of high-fluoride group was significantly higher than that of low-fluoride group(P < 0.05). In high-fluoride group, the mRNA expressions of α3, α4 and α7 nAChR subunits in rat brains(1.51 ± 0.20,1.45 ± 0.06,1.63 ± 0.08) were significantly lower as compared to controls (1.79 ± 0.11,1.66 ± 0.14,1.83 ± 0.06, all P< 0.05); whereas there were no significant changes in mRNA levels of these receptor subunits of the rat brains between low-fluoride group(1.65 ± 0.17,1.59 ± 0.09,1.71 ± 0.03) and controls (all P > 0.05). Furthermore, the protein levels of α3, α4 and α7 nAChR subunits in rat brains of highfluoride group(0.58 ± 0.13,0.16 ± 0.03,1.41 ± 0.38) and low-fluoride group(0.56 ± 0.23,0.08 ± 0.02,0.51 ± 0.16) were significantly lower than those of controls( 1.48 ± 0.42,0.57 ± 0.21,2.56 ± 0.26, P<0.05 or < 0.01). Conclusions Decreased ability of learning and memory in coal-burning type of fluorosis rats may be associated with declined expressions of nAChR at proteins and mRNA levels, which might be the main mechanism of the behavior change.     

阿尔茨海默病患者血浆胆碱酯酶活性改变的临床意义

目的探讨血浆中两种胆碱酯酶(ChE),即乙酰胆碱酯酶(AChE)和丁酰胆碱酯酶(Butyrylcholinesterase,BuChE)的活性在阿尔茨海默病(AD)发病机制中的意义和临床诊断价值。方法选择经临床确诊的29例AD患者并33例健康老年人,采用改进的Ellman比色法分别测定血浆中AChE及BuChE活性,并进行相关比较分析。结果AD患者血浆AChE活性(1.39±0.57)nmol/(min.ml)较正常老年人(2.16±0.86)nmol/(min.ml)低(P<0.001);而BuChE活性在AD患者和正常老年人之间无显著差异;两种ChE活性在性别和年龄间的差异均无统计学意义。结论AD患者血浆AChE活性较正常老年人明显降低,这种降低与性别和年龄无关。血浆ChE活性的测定可作为AD的一种辅助诊断指标。     

贵州省江口县土家族葡萄糖-6-磷酸脱氢酶基因突变分析

目的 了解贵州省江口县土家族葡萄糖-6-磷酸脱氢酶（G6PD）缺陷症的基因频率、基因突变类型特点及分布特征，从分子水平揭示G6PD基因多态性。方法 采集世居当地土家族男性血液样本227例，用四氮唑蓝（NBT）纸片定性法及G6PD／6PGD比值法做G6PD缺陷症筛查。确诊者用错配引物介导的聚合酶链反应／限制性内切酶酶切分析法（PCR-RE）进行中国人常见9种G6PD基因突变型分析，突变特异性扩增系统法（ARMS）验证其中3种突变。结果227名土家族男性中检出17例G6PD缺陷者，总检出率7．49％，G6PD缺陷症基因频率0．0749。基因分析检出cDNA1388（G→A）12例，在G6PD缺陷者中的基因频率为0．706，未知突变5例，基因频率为0．294。结论 G6PD缺陷症在贵州土家族人群有着较高的基因频率，其主要突变类型为G6PD基因cDNA1388（G→A）。     

贵州从江侗族和江口土家族人群β-地中海贫血基因突变型的研究

目的了解β-地中海贫血在贵州从江县侗族、江口县土家族中的基因类型特点、基因型频率及分布规律。方法采用抗碱血红蛋白(HbF)和血红蛋白A2(HbA2)定量测定对人群进行β-地中海贫血初筛,同时应用全自动血细胞分析仪进行RBC、Hb、HCT、MCV、MCH、MCHC、RDW等7项血液学指标分析,用常规酚-氯仿抽提法提取筛查阳性受检者DNA,经PCR-反向点杂交法对β珠蛋白基因进行突变分析。结果受检982人中,共检出52例β-地中海贫血携带者,总检出率为5.27%,其中侗族、土家族检出率分别为7.85%、2.68%;经β珠蛋白突变基因分析,在这两个民族中检出中国人常见3种突变类型:CD17(A→T)无义突变(39例,75.00%),CD41-42(TCTT)移码突变(12例,23.07%)和βE(Codon26)(1例,1.92%)。结论在贵州省少数民族中β-地中海贫血有很高的发病率,基因突变类型具有显著的民族特征,β珠蛋白基因变异情况很独特,可能与族内婚配、家族发病聚集性和通婚地域半径狭小有关。     

燃煤型氟中毒对大鼠脑组织NO含量及NOS mRNA和蛋白表达的影响

目的观察燃煤型氟中毒对大鼠脑组织NO含量及NOS mRNA和蛋白表达的影响。方法健康SD大鼠24只,体质量100～120 g,按体质量随机分为3组,每组8只。对照组饲以常规饲料,低氟组和高氟组以氟病区燃煤烘烤的玉米为主要饲料(含氟量分别为11.30、104.20 mg/kg),来复制氟中毒大鼠模型,染氟时间为3个月。用氟离子选择电极法检测动物尿氟、骨氟、脑氟含量,观察大鼠海马CA1区神经元病理变化,用Biomias 2000图像分析系统测试大鼠海马CA1区神经元胞体平均面积、周长及平均灰度值,比色法测定脑组织NOS活性,硝酸还原酶法测定脑组织NO含量,蛋白印迹方法测定NOS蛋白水平;实时荧光定量PCR方法测定NOS mRNA水平。结果低、高氟组大鼠尿氟为(2.61±0.11)(4.39±0.13) mg/L,骨氟(2 734±137)(4 323±203) mg/kg,脑氟(1.00±0.08)(1.14±0.02) mg/kg;与对照组尿氟(1.59±0.10) mg/L、骨氟(1 399±152) mg/kg、脑氟(0.41±0.06) mg/kg比较,差异有统计学意义(P0.05或P0.01);尼氏染色显示,与对照组大鼠神经元平均灰度值(119.0±9.7)比较,染氟组大鼠均明显增加[低氟(153.0±8.9),高氟(159.4±2.9)];低氟组、高氟组大鼠脑组织总NOS活性[(8.57±2.40)、(11.49±3.10) kU/g]较对照组(16.80±3.20) kU/g显著性下降(P0.05),高氟组大鼠脑组织NO含量(2.05±0.25)μmol/L较对照组(4.68±1.78)μmol/L显著性降低(P0.05)。低氟组、高氟组大鼠脑组织NOS蛋白表达水平[(0.53±0.24),(0.82±0.28)]较对照组(0.17±0.02)显著增加(P0.05/0.01),低氟组、高氟组大鼠脑组织NOS mRNA水平[(1.37±0.07),(1.38±0.08)]均较对照组(1.53±0.17)显著下降(P0.05)。结论低剂量氟具有一定神经毒性,表现为食用燃煤型氟中毒病区燃煤烘烤的粮食低剂量、早期可导致动物脑氟含量增高,使大鼠海马CA1区神经元蛋白合成功能下降,脑组织NOS活性、NO含量、NOS蛋白及mRNA表达改变。     

贵州省地方性氟中毒地区人群GSTP1基因Ile105Val位点多态性分析

Objective To investigate plasma glutathione S-transferase(GSTs) activity and GSTP1 gene Ile105Val polymorphism in Bijie City, Guizhou Province, a coal-burning fluorosis endemic area. Methods One hundred and sixty villagers from Yachi Twon using non-improved cooking stoves were selected as the non-intervened group in Bijie City, Guizhou Province where coal-burning fluorosis was prevailing; 153 villagers as the intervented group were chosen from Changchun Twon, where cooking stoves were improved; 151 villagers were served as the control group from Baiyunshan Twon, Changshun County without endemic fluorosis. The activity of GSTs was tested by colorimetric analysis with spectrophotometer. The genotype of the GSTP1 gene Ile105Val polymorphism, presenting as either homozygous wild-type (AA), or heterozygous mutation type (AG), or homozygous mutation type (GG), was detected through the PCR-RFLP procedure. Results The activity of GSTs in plasma of non-intervened group [(12.44±4.97) kU/L]was significantly lower than that of intervened group (P < 0.05), and that of intervened group[(20.78±6.20)kU/L]was significantly lower than that of control group[(24.30±6.27)kU/L, P< 0.05]. The difference of the enzyme activity of three groups were statistically significant (F = 51.71, P < 0.05), but this enzyme activity did not vary significantly in each sex of each grnup(P > 0.05). Compared intervened group [AA:67.3%(103/153), AG:29.4%(45/153),GG:3.3%(5/153)]and non-intervened group[AA:66.9%(107/160), AG:30%(48/160), GG:3.1%(5/160)]with control group[AA:74.8%(113/151), AG:25.2%(38/151), GG:0 (0/151)], the Ile105Val polymorphism site of GSTP1 gene had significant difference(χ2= 6.04,6.07, both P< 0.05), but not significant between intervened and non-intervened groups(χ2 = 0.02, P>0.05). Conclusions Fluorosis can decrease the activity of GSTs and introduce the GSTP1 gene Ile105Val polymorphism, intervention with the fluorine intake will improve the effect of fluoride on the body.     

贵州省地方性氟中毒地区人群GSTP1基因Ile105Val位点多态性分析

Objective To investigate plasma glutathione S-transferase(GSTs) activity and GSTP1 gene Ile105Val polymorphism in Bijie City, Guizhou Province, a coal-burning fluorosis endemic area. Methods One hundred and sixty villagers from Yachi Twon using non-improved cooking stoves were selected as the non-intervened group in Bijie City, Guizhou Province where coal-burning fluorosis was prevailing; 153 villagers as the intervented group were chosen from Changchun Twon, where cooking stoves were improved; 151 villagers were served as the control group from Baiyunshan Twon, Changshun County without endemic fluorosis. The activity of GSTs was tested by colorimetric analysis with spectrophotometer. The genotype of the GSTP1 gene Ile105Val polymorphism, presenting as either homozygous wild-type (AA), or heterozygous mutation type (AG), or homozygous mutation type (GG), was detected through the PCR-RFLP procedure. Results The activity of GSTs in plasma of non-intervened group [(12.44±4.97) kU/L]was significantly lower than that of intervened group (P < 0.05), and that of intervened group[(20.78±6.20)kU/L]was significantly lower than that of control group[(24.30±6.27)kU/L, P< 0.05]. The difference of the enzyme activity of three groups were statistically significant (F = 51.71, P < 0.05), but this enzyme activity did not vary significantly in each sex of each grnup(P > 0.05). Compared intervened group [AA:67.3%(103/153), AG:29.4%(45/153),GG:3.3%(5/153)]and non-intervened group[AA:66.9%(107/160), AG:30%(48/160), GG:3.1%(5/160)]with control group[AA:74.8%(113/151), AG:25.2%(38/151), GG:0 (0/151)], the Ile105Val polymorphism site of GSTP1 gene had significant difference(χ2= 6.04,6.07, both P< 0.05), but not significant between intervened and non-intervened groups(χ2 = 0.02, P>0.05). Conclusions Fluorosis can decrease the activity of GSTs and introduce the GSTP1 gene Ile105Val polymorphism, intervention with the fluorine intake will improve the effect of fluoride on the body.     

神经型尼古丁乙酰胆碱受体在阿尔茨海默病中的神经保护作用

老年性痴呆主要分为三种:一种叫阿尔茨海默病(AD),其最为常见,大约占68%;第二种叫血管性痴呆(VD),是一种由于血供不足引起的不同大脑区域损伤所致的渐进性认知障碍;第三种是以上两种病症并存,叫混合性痴呆。AD是一种主要在老年期发生的以进行性痴呆为主要特征的神经元退行性变