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目的探讨低浓度甲醛吸入后大鼠离体海马脑片长时程增强(LTP)的变化及此变化是否具有年龄差异性。方法选取健康Wistar大鼠32只。其中成年鼠和幼年鼠各12只,新生鼠8只。每个年龄段的大鼠随机分为对照组和甲醛染毒组。甲醛染毒组大鼠暴露于质量浓度为0.5 mg.m-3甲醛,染毒时间为每天2 h,连续30 d。染毒结束后制作离体海马脑片,利用膜片钳技术记录高频刺激(HFS)后海马脑片LTP,并分析兴奋性突触后场电位(fEPSP)的斜率和幅度变化。结果各年龄段甲醛染毒组在HFS后的第30分钟fEPSP的斜率和幅度均较同龄对照组降低。新生鼠中甲醛染毒组与对照组海马脑片HFS后30 min fEPSP的斜率分别为(118.1±9.7)%和(281.8±40.2)%,差异有统计学意义(P<0.01);在幼年鼠,甲醛染毒组与对照组海马脑片HFS后30 min fEPSP的斜率分别为(107.7±5.2)%和(289.5±64.7)%,差异有统计学意义(P<0.05);在成年鼠,甲醛染毒组与对照组海马脑片HFS后30 min fEPSP的斜率分别为(120.7±6.5)%和(197.9±38.1)%,无统计学差异(P>0.05)。新生鼠甲醛染毒组与其对照组海马脑片HFS后30 min fEPSP的幅度分别为(111.1±4.9)%和(293.4±46.8)%,差异有统计学意义(P<0.01);幼年鼠甲醛染毒组与其对照组海马脑片HFS后30 min fEPSP的幅度分别为(101.9±4.2)%和(266.9±51.0)%,差异有统计学意义(P<0.05);成年鼠甲醛染毒组与其对照组海马脑片HFS后30 min fEPSP的幅度分别为(122.9±4.2)%和(191.2±33.6)%,无统计学差异(P>0.05)。结论甲醛吸入染毒可抑制Wistar大鼠海马LTP的形成,且这种抑制作用具有年龄差异性,年龄越小,甲醛所造成的损伤越大。
Objective To investigate the changes of long-term potentiation (LTP) in isolated rat hippocampal slices after inhalation of low concentration of formaldehyde and whether the changes have age-related changes. Methods Thirty-two healthy Wistar rats were selected. Including 12 adult rats and juvenile rats, 8 newborn rats. Rats of each age group were randomly divided into control group and formaldehyde exposure group. Formaldehyde exposure group rats exposed to 0.5 mg.m-3 formaldehyde, the exposure time was 2 h per day for 30 days. The hippocampal slices of hippocampal slices were recorded after the exposure to high frequency stimulation (HFS) using patch clamp technique. The changes of slope and amplitude of excitatory postsynaptic field potential (fEPSP) were analyzed. Results The slope and amplitude of fEPSP at the 30th minute after HFS in the formaldehyde-exposed group were lower than those in the same age group. The slope of fEPSP was (118.1 ± 9.7)% and (281.8 ± 40.2)% respectively at 30 min after HFS in formalin-exposed group and control group, the difference was statistically significant (P <0.01) , The slope of fEPSP at 30 min after HFS in formalin-exposed and control groups was (107.7 ± 5.2)% and (289.5 ± 64.7)%, respectively, with a significant difference (P <0.05) The slopes of fEPSP at 30 min after exposure to HFS in exposed and untreated groups were (120.7 ± 6.5)% and (197.9 ± 38.1)%, respectively, with no significant difference (P> 0.05). The amplitude of fEPSP at 30 min after exposure to formaldehyde in neonatal rats and the control group was (111.1 ± 4.9)% and (293.4 ± 46.8)%, respectively, and the difference was statistically significant (P <0.01) The amplitude of fEPSP at 30 min after HFS in the control group and the control group was (101.9 ± 4.2)% and (266.9 ± 51.0)%, respectively, with statistical significance (P <0.05) The amplitude of fEPSP at 30 min after HFS was (122.9 ± 4.2)% and (191.2 ± 33.6)%, respectively, with no significant difference (P> 0.05). Conclusions Formalin inhalation can inhibit the formation of LTP in the hippocampus of Wistar rats. The inhibitory effect of LTP is age-differentiated. The younger the age, the greater the damage caused by formaldehyde.