摘要目的 研究低硒、低碘及其联合对亲代和子代大鼠骨、软骨生长的影响.方法 48只断乳SD健康大鼠,按体质量随机分对照组、低硒组、低碘组和低硒低碘组,每组12只.4组大鼠分别采用人工配制的低硒、低碘、低硒低碘及含硒、碘量正常的饲料喂饲.大鼠饲养8周后(约3月龄)进行组内繁殖;亲代大鼠喂饲至6月龄、子代大鼠喂饲至3月龄时,取亲代和子代大鼠血样,测定血清硒及T3、T4;取大鼠右侧胫骨及左侧膝关节.用游标卡尺测定胫骨长度、中段额状横径、胫骨上端关节软骨横径、纵径;膝关节包埋切片后,光镜下测定胫骨近端生长板厚度、生长板软骨肥大层、增殖层细胞层数.结果 低硒对亲代和子代大鼠血清硒有明显影响(F值分别239.56、232.68,P均<0.05),对于代血清T4水平也有明显影响(F=6.95,P<0.05);低碘对亲代和子代大鼠血清T3、T4均有明显影响(F值分别为14.11、14.05,30.29、34.53,P<0.01),低硒、低碘联合对子代大鼠血清T4水平的影响存在交互作用(F=5.99,P<0.01).亲代和子代大鼠血清硒,低硒组[(30.28±6.34)、(43.95±9.75)μg/L]、低硒低碘组[(30.33±5.18)、(35.40±3.06)μg/L]均明显低于低碘组[(345.83±29.55)、(245.24±9.95)μg/L]、对照组[(358.64±30.50)、(236.50±9.75),P均<0.05].低硒低碘组[(0.55±0.05)、(0.88±0.14)mmol/L]亲代和子代大鼠血清T3均明显低于对照组[(0.75±0.08)、(1.26±0.26)mmol/L,P均<0.05],低碘组[(24.11±2.29)、(42.10±8.92)mmol/L]、低硒低碘组[(20.66±1.93)、(26.55±5.98)mmol/L]亲代和子代大鼠血清T4均明显低于对照组[(36.15±2.74)、(52.79±8.84)mmol/L]和低硒组[(28.12±3.33)、(52.02±11.99)mmol/L,P均<0.05];低硒低碘组子代大鼠血清T4明显低于低碘组(P<0.05).子代大鼠中,低硒,低碘对胫骨长度、生长板厚度、增殖细胞层数、肥大细胞层数影响明显(F值分别为24.31、6.98,40.76、56.15,25.24、82.82,10.07、5.57,P<0.01或<0.05).低硒和低碘对胫骨长度、生长板厚度、增殖细胞层数、肥大细胞层数的影响存在交互作用(F值分别为5.68、24.86、41.82、9.12,P<0.05或<0.01);低硒组[(33.17±0.34)mm]、低硒低碘组胫骨长度[(31.30±0.87)mm]明显低于对照组[(34.12±0.32)turn,P均<0.05];低硒低碘组生长板厚度[(1.60±0.18)mm、增殖细胞层数(8.54±0.81)、肥大细胞层数(4.95±0.37)明显低于低硒组[(3.03±0.10)mm、14.68±0.84、6.60±0.31]、低碘组[(2.90±0.09)mm,13.75±0.33、6.61±0.84]及对照组[(3.19±0.09)mm、14.94±0.36、6.64±0.26,P均<0.05)];低碘组生长板厚度、增殖细胞层数小于对照组(P<0.05).结论 低硒影响子代大鼠胫骨生长,低碘影响子代大鼠软骨细胞增殖,降低生长板厚度,低硒低碘联合显著影响子代大鼠骨、软骨的生长.

abstractsObjective To study the effects of selenium deficiency,iodine deficiency and combined selenium and iodine deficiency on bone and cartilage growth in the parental and the first filial generation rats. Methods Forty-eight weanling healthy SD rats were randomly divided into selenium deficieney, iodine deficiency, combined selenium and iodine deficiency and control groups according to their body mass. These rats were fed with selenium deficiency, iodine deficiency, combined selenium and iodine deficiency, and normal fodder, respectively. The parental rats (about 3 months old) were mated in each group 8 weeks after the beginning of the experiment. Right tibias and left knee joints were collected when the parental generation rats were about 6 months and the first filial generation rats were about 3 months old. Tibial length, mid-shaft tibial diameter, and articular cartilage diameters of the right tibias were measured by vernier caliper. Left knee joints were embedded and cut into sections and the thickness of the growth plate cartilage, layers of proliferative and hypertrophic chondrocytes in growth plate cartilage were observed under the light microscope. Results The selenium deficiency had significant effect on serum selenium level of the parental and the first filial generation rats(F value were 239.56,232.68, P< 0.01), and also on serum T4 level of the first filial generation rats(F value were 6.95, P < 0.05). The iodine deficiency had significant effect on serum T3 and T4 level in the two generations rats(F value were 14.11,14.05,30.29,34.53, P < 0.01 ). There were interactions between selenium deficiency and iodine deficiency on serum T4 level in the first filial generation rats (F= 5.99, P< 0.05). The serum selenium of selenium deficiency group[ (30.28 ± 6.34), (43.95 ± 9.75)μg/L],combined selenium and iodine deficiency group[ (30.33 ± 5.18), (35.40 ± 3.16)μg/L] were significantly lower than iodine deficiency group[(345.83 ± 29.55), (245.24 ± 9.95)μg/L] and the controls[ (358.64 ± 30.50), (236.50 ±9.75) μg/L] in the two generations. The serum T3 of combined selenium and iodine deficiency group [(0.55 ± 0.05 ),(0.88 ± 0.14)nmol/L] were significantly lower than the controls[(0.75 ± 0.08), (1.26 ± 0.26)nmol/L] in the two generations. The serum T4 of iodine deficiency [ (24.11 ± 2.29), (42.10 ± 8.92) nmol/L ] and combined selenium and iodine deficiency group[ (20.66 ± 1.93), (26.55 ± 5.98)nmol/L] were significantly lower than the controls[ (36.15 ±2.74), (52.79 ± 8.84)nmol/L] and selenium deficiency group[ (28.12 ± 3.33), (52.02 ± ll.99)nmol/L] in the two generations. The selenium deficiency and iodine deficiency had significant effect on tibial length, thickness of the growth plate cartilage, layers of proliferative and hypertrophic chondrocytes in first filial generation rats(F values were 24.31,6.98,40.76,56.15,25.24,82.82, 10.07,5.57, P <0.05 or <0.01). There were interactions between selenium deficiency and iodine deficiency on tibial length, thickness of the growth plate cartilage, layers of proliferative and hypertrophic chondrocytes (F values were 5.68,24.86,41.82,9.12, P <0.05 or <0.01 ). The tibial length of the selenium deficiency group[ (33.17 ± 0.34)mm] and combined selenium and iodine deficiency group[ (31.30 ± 0.87)mm] were significantly lower than the controls[ (34.12 ± 0.32)mm, P< 0.05]. Thickness of the growth plate cartilage [ (1.60 ± 0.18)mm ], layers of proliferative chondrocyte (8.54 ± 0.81), and hypertrophic chondrocyte (4.95 ± 0.37)of the combined selenium and iodine deficiency group were significantly decreased when compared to the selenium deficiency group[ (3.03 ± 0.10)mm, 14.68 ± 0.84,6.60 ± 0.31], iodine deficiency group[ (2.90 ± 0.09)mm, 13.75 ±0.33,6.61 ± 0.84 ] and the controls [ (3.19 ± 0.09) mm, 14.94 ± 0.36, 6.64 ± 0.26, P <0.05]. Thickness of the growth plate cartilage, layers of proliferative chondrocyte of the iodine deficiency group were lower than the controls(P<0.05). Conclusions Selenium deficiency impair tibial growth in first filial generation rats, iodine deficiency retarded the chondroncyte proliferation and decreases the thickness of growth plate cartilage in first filial generation rats, and combined selenium and iodine deficiency significantly impair the growth of bone and cartilage in first filial generation rats.