【摘要】 目的 探讨褪黑素(melatonin, MEL)对氟染毒子代大鼠焦虑样行为及炎性相关因子表达的影响。方法 选用8周龄SD大鼠12只(雌雄比为2∶1),随机分为对照组和氟染毒组(n=6),自由饮用普通纯净水和含100 mg/L氟化钠(sodium fluoride, NaF)的纯净水，2个月后，雌雄鼠2∶1合笼，子代大鼠出生后第一天(postnatal day0)记为PND0。PND21断乳时，将对照组和氟染毒组子代大鼠分别分为子代对照组(C)、子代褪黑素组(MEL)、氟染毒子代对照组(F)和氟染毒子代褪黑素组(FM)(n=10),每晚19:00—20:00间将20 mg/kg的MEL和乙醇生理盐水分别灌胃给予相应组别大鼠。PND60,采用旷场试验和高架试验观察各组子代大鼠的行为学变化；尼氏染色检测海马神经元尼氏小体数量的变化情况；酶联免疫吸附测定法(enzyme linked immunosorbent assay, ELISA)检测血清中促炎细胞因子白细胞介素-1β(interleukin-1β,IL-1β)、肿瘤坏死因子-α(tumor necrosis factor-α,TNF-α)、抗炎细胞因子白细胞介素-10(interleukin-10,IL-10)的含量；qRT-PCR法检测海马组织中IL-1β、TNF-α和IL-10的mRNA表达水平；Western Blot法检测海马组织中IL-1β、TNF-α和IL-10的蛋白表达。结果 与C组相比，F组子代大鼠中央停留时间显著减少、周围停留时间显著增加(P<0.05),海马神经元中尼氏小体数量减少；与F组相比，FM组子代大鼠中央停留时间显著增加、周围停留时间显著减少(P<0.05),且尼氏小体数量增加。ELISA结果显示，与C组相比，F组子代大鼠血清中IL-10含量显著下降(P<0.05);与F组相比，FM组子代大鼠血清中IL-1β、TNF-α的含量显著下降，IL-10的含量显著升高(P<0.05)。qRT-PCR和Western Blot结果均显示，与C组相比，F组子代大鼠海马组织TNF-α蛋白的表达水平显著升高(P<0.05)。Western Blot结果显示，与F组相比，FM组子代大鼠海马组织TNF-α蛋白的表达水平显著下降(P<0.05)。结论 MEL可通过促进血清和海马组织中抗炎细胞因子的表达，抑制血清和海马组织中促炎细胞因子的表达，进而缓解氟染毒子代大鼠的焦虑样行为。更多还原

【Abstract】 Objective To investigate the effects of melatonin(MEL) on anxiety-like behavior and expression of inflammatory-related cytokines in offspring rats exposed to fluoride.Methods Twelve 8-week-old SD rats(8 females and 4 males) were randomly divided into control group and fluoride exposure group(n=6), and had free access to ordinary pure water or pure water containing 100 mg/L sodium fluoride. After two months, female and male rats were raised together in cages at a ratio of 2∶1. The first postnatal day(PND) of offspring rats was recorded as PND0. After weaning on PND21, the offspring rats from the control group and fluoride exposure group were divided into offspring control group(group C),melatonin exposure group(group MEL), fluoride exposure group(group F) and fluoride-melatonin exposure group(group FM)(n=10). MEL and ethanol saline at 20 mg/kg were given to the corresponding groups by gavage from 19:00 to 20:00 every night. On PND60, an open field test and an elevated plus maze test were used to observe the behavioral changes of offspring rats in each group. Nissl staining was used to determine the changes in the number of Nissl bodies in hippocampal neurons. An enzyme linked immunosorbent assay(ELISA) was used to measure the contents of pro-inflammatory cytokine interleukin-1β(IL-1β), tumor necrosis factor-α(TNF-α), and anti-inflammatory cytokine interleukin-10(IL-10) in serum. The mRNA expression levels of IL-1β, TNF-α, and IL-10 in the hippocampus were determined by the quantitative reverse transcription-polymerase chain reaction(qRT-PCR). The Western Blot method was used to determine the protein expression of IL-1β, TNF-α, and IL-10 in the hippocampus.Results Compared with the group C, the offspring rats in the group F showed significantly decreased central residence time and increased surrounding residence time(P<0.05) and decreased number of Nissl bodies in hippocampal neurons. Compared with the group F, the group FM showed significantly higher central residence time and lower surrounding residence time(P<0.05) and higher Nissl bodies. The results of ELISA showed that the content of IL-10 in serum of the offspring rats decreased significantly in the group F compared with the group C(P<0.05); the contents of IL-1β and TNF-α decreased significantly and the content of IL-10 increased significantly in serum of the offspring rats in the group FM compared with the group F(P<0.05). Both qRT-PCR and Western Blot results showed that the expression level of TNF-α protein in the hippocampus of the offspring rats was significantly higher in the group F than in the group C(P<0.05), and significantly lower in the group FM than in the group F in Western Blot result(P<0.05).Conclusion MEL alleviates the anxiety-like behavior of fluoride-exposed offspring rats by promoting the expression of anti-inflammatory cytokines in serum and the hippocampus and inhibiting the expression of pro-inflammatory cytokines in serum and the hippocampus.更多还原