Intervention effect of HSP60 on learning and memory impairment induced by combined exposure to lead and hypertension in mice / 中国职业医学

ObjectiveTo investigate the intervention effect of heat shock protein 60 (HSP60) on learning and memory impairment induced by combined exposure to lead and hypertension in mice, and the relative mechanism of triggering receptor expressed on myeloid cells 2 (TREM2). Methods Specific pathogen-free C57BL/6J male mice were randomly divided into control group, hypertension group, lead-exposed group and lead-exposed + hypertension group, or into control group, heat shock protein 60 (HSP60) control group, lead-exposed + hypertension group and HSP60 intervention group, with 10 mice in each group. Mice of hypertension group and lead-exposed + hypertension group were intraperitoneally injected with angiotensin Ⅱ at a dose of 0.5 mg/(kg·d) for seven consecutive days to induce hypertension model. Mice of the lead-exposed group, lead-exposed + hypertension group, and HSP60 intervention group were given lead acetate drinking water with a mass concentration of 250.0 mg/L, while mice in the control group, hypertension group, and HSP60 control group were given purified water for 12 weeks. Mice of the HSP60 control group and HSP60 intervention group were intraperitoneally injected with a solution of HSP60 at a dose of 4 mg/kg body weight, every other day for a total of three times at the 12th week. The learning and memory ability of mice was detected using the Morris water maze test. The enzyme-linked immunosorbent assay was used to detect the levels of interleukin (IL)-1β, IL-6 and tumor necrosis factor-α (TNF-α) in the hippocampal tissues of the mice. The relative expression of ionized calcium binding adaptor molecule-1 (IBA1) and TREM2 protein in the hippocampus of mice was detected using Western blot. Results i) The number of platform crossings of the mice in the hypertension group and the lead-exposed group was lower than that in the control group (both P<0.05). The escape latency of the mice on the third day was longer and the number of platform crossings was lower in the lead-exposed + hypertension group compared with the control group, hypertension group and lead-exposed group (all P<0.05). The levels of IL-1β, IL-6, and TNF-α in the hippocampus of the other three groups increased compared with the control group (all P<0.05). The relative expression of IBA1 protein in the hippocampus of lead-exposed group and lead-exposed + hypertension group increased (all P<0.05), while the relative protein expression of TREM2 decreased compared with the control group (all P<0.05). The levels of IL-1β, IL-6, TNF-α, and the relative protein expression of IBA1 protein in the hippocampus of the lead-exposed+hypertension group were higher (all P<0.05), and relative expression of TREM2 protein was lower (P<0.05) than those in the hypertension group. The level of TNF-α and the relative expression of IBA1 protein in the hippocampus of lead-exposed+hypertension group were higher than those in lead-exposed group (all P<0.05). ii) The escape latency of mice in the lead-exposed + hypertension group was longer than that in the control group (P<0.05), and the number of platform crossings was fewer than that in the control group (P<0.05). The escape latency of mice in the HSP60 intervention group was shortened (P<0.05), the number of platform crossings increased (P<0.05), and the levels of IL-1β, IL-6, TNF-α and relative expression of IBA1 protein decreased in the hippocampus (all P<0.05), while the relative expression of TREM2 protein increased (P<0.05) compared with the lead-exposed+hypertension group. Conclusion Combined exposure of lead and hypertension has a synergistic effect on learning and memory impairment in mice. The mechanism may be related to the inhibition of TREM2 expression by lead in the hippocampus of hypertensive mice and aggravating the neuroinflammatory response. Intervention with TREM2 receptor agonist HSP60 can alleviate learning and memory impairment in mice exposed to lead and hypertension by up-regulating TREM2 expression in the hippocampus.

Effects of electroacupuncture on postoperative cognitive dysfunction and AngⅡ/AT1R in the hippocampus in aging rats induced by D-galactose / 中国针灸

<p><b>OBJECTIVE</b>To observe the effects of electroacupuncture (EA) on postoperative cognitive dysfunction (POCD) and AngⅡ/AT1R in the hippocampus in D-galactose-induced aging rats which received hepalobectomy, and to explore the possible mechanism of EA on POCD.</p><p><b>METHODS</b>Eighty male Sprague-Dawley rats were randomly divided into a young control group (10 rats), a D-Galactose-induced aged (Da) group (10 rats), a Da+hepatolobectomy group (30 rats) and an EA group (30 rats). The rats in the Da+hepatolobectomy group and EA group were further randomly divided into a 1 d subgroup, 3 d subgroup and a 7 d subgroup, 10 rats in each subgroup. The rats in the EA group were treated with EA at "Baihui" (GV 20) and "Dazhui" (GV 14) with continuous wave (15 Hz in frequency and 1 mA in intensity), and rats in each subgroup were treated for 1 d, 3 d and 7 d, respectively. The rats in the remaining groups were treated with immobilization, once a day. The Y-maze was used to observe the behavior change of rats, and ELISA was applied to measure the level of hippocampal AngⅡ, and RT-PCR and immunohistochemistry method were performed to detect AT1R mRNA expressions and AT1R positive expression in the hippocampus.</p><p><b>RESULTS</b>The number of rat initiative avoidance in the Da group was significantly less than that in the young control group (<0.05), and the mRNA expression and positive percentage of AT1R in the hippocampus in the Da group were significantly higher than those in the young control group (both<0.01). Compared with the Da group, the number of rat initiative avoidance in each subgroup of Da+hepatolobectomy group and EA group were significantly reduced (all<0.01), and the expression of AngⅡ, AT1R mRNA and AT1R positive cells percentage in the hippocampus were significantly increased (<0.05,<0.01). The number of rat initiative avoidance in each subgroup of EA group was higher than that in the subgroup of Da+hepatolobectomy group (<0.05,<0.01); and the expression of AngⅡ, AT1R mRNA, and AT1R positive percentage in the EA group were significantly less than that in the Da+hepatolobectomy group (<0.05,<0.01).</p><p><b>CONCLUSIONS</b>EA at "Baihui" (GV 20) and "Dazhui" (GV 14) could improve POCD in D-galactose-induced aging rats which received hepalobectomy, and it is likely to be related with the inhibition of AngⅡ, AT1R positive expression and AT1R mRNA in the hippocampus.</p>

Effects of nano-lead exposure on learning and memory as well as iron homeostasis in brain of offspring rats / 中华劳动卫生职业病杂志

<p><b>OBJECTIVE</b>To investigate the effects of nano-lead exposure on learning and memory and iron homeostasis in the brain of the offspring rats on postnatal day 21 (PND21) and postnatal day 42 (PND42).</p><p><b>METHODS</b>Twenty adult pregnant female Sprague-Dawley rats were randomly divided into control group and nano-lead group. Rats in the nano-lead group were orally administrated 10 mg/kg nano-lead, while rats in the control group were administrated an equal volume of normal saline until PND21. On PND21, the offspring rats were weaned and given the same treatment as the pregnant rats until 42 days after birth. The learning and memory ability of offspring rats on PND21 and PND42 was evaluated by Morris water maze test. The hippocampus and cortex s amples of offspring rats on PND21 and PND42 were collected to determine iron and lead levels in the hippocampus and cortex by inductively coupled plasma-mass spectrometry. The distributions of iron in the hippocampus and cortex were observed by Perl's iron staining. The expression levels of ferritin, ferroportin 1 (FPN1), hephaestin (HP), and ceruloplasmin (CP) were measured by enzyme-linked immunosorbent assay.</p><p><b>RESULTS</b>After nano-lead exposure, the iron content in the cortex of offspring rats on PND21 and PND42 in the nano-lead group was significantly higher than those in the control group (32.63 ± 6.03 µg/g vs 27.04 ± 5.82 µg/g, P<0.05; 46.20 ±10.60 µg/g vs 36.61 ± 10.2µg/g, P<0.05). The iron content in the hippocampus of offspring rats on PND42 in the nano-lead group was significantly higher than that in the control group (56.9 ± 4.37µg/g vs 37.71 ± 6.92µg/g, P<0.05). The Perl's staining showed massive iron deposition in the cortex and hippocampus in the nano-lead group. FPNl level in the cotfex of offspring rats on PND21 in the nano-lead group was significantly lower than that in the control group (3.64 ± 0.23 ng/g vs 4.99 ± 0.95 ng/g, P<0.05). FPN1 level in the hippocampus of offspring rats on PND42 in the nano-lead group was significantly lower than that in the control group (2.28 ± 0.51 ng/g vs 3.69 ± 0.69 ng/g, P<0.05). The escape latencies of offspring rats on PND21 and PND42 in the nano-lead group were longer than those in the control group (15.54 ± 2.89 s vs 9.01 ± 4.66 s; 6.16 ± 1.42 s vs 4.26 ± 1.51 s). The numbers of platform crossings of offspring rats on PND21 and PND42 in the nano- lead group were significantly lower than those in the control group (7.77 ± 2.16 times vs 11.2 ± 1.61 times, P<0.05; 8.12 ± 1.51 times vs 13.0 ± 2.21 times, P<0.05).</p><p><b>ONCLUSION</b>n Nano-lead exposure can result in iron homeostasis disorders in the hippocampus and cortex of offspring rats and affect their learning and memory ability.</p>