Effects of folic acid, vitamin B(6) and vitamin B(12) on learning and memory function in cerebral ischemia rats / 中华预防医学杂志

<p><b>OBJECTIVE</b>To investigate the effects of folic acid, vitamin B(6) and B(12) on plasma homocysteine and on learning and memory functions in focal cerebral ischemia rats.</p><p><b>METHODS</b>Sprague-Dawley rats were randomly divided into four groups. They were sham operation group (Sham OP), middle cerebral artery occlusion model group (MCAO), MCAO + folic acid group (MCAO + FA) and MCAO + compound vitamin (folate, vitamin B(6) and B(12)) group (MCAO + CV). Plasma homocysteine was measured before and after supplementation and after ischemia.</p><p><b>RESULTS</b>The level of plasma homocysteine in MCAO + FA and MCAO + CV groups were significantly lower than those in Sham OP and MCAO groups after supplementation and ischemia (6.92 +/- 1.04) micromol/L and (5.49 +/- 1.00) micromol/L vs (9.33 +/- 1.11) micromol/L, (10.90 +/- 2.03 micromol/L), P < 0.05. While in MCAO + CV group was lower than that in MCAO + FA group (5.49 +/- 1.00) micromol/L vs (6.92 +/- 1.04) micromol/L, P < 0.05. The neurological deficit scores and shock times in Y-type maze of MCAO + FA and MCAO + CV groups were lower than those in MCAO group (1.75 +/- 0.46 and 1.38 +/- 0.52 vs 2.62 +/- 0.52; 123.50 +/- 39.77 and 86.25 +/- 21.39 vs 173.25 +/- 46.32, P < 0.05). The correct times of MCAO + CV group in Y-type maze was higher than that in MCAO group (3.75 +/- 0.42 vs 2.12 +/- 0.45, P < 0.05).</p><p><b>CONCLUSION</b>Folic acid intake could not only reduce plasma homocysteine concentration but also promote the recovery of the learning and memory functions of rats with cerebral ischemia. The effects of folic acid combined with vitamin B(6) and vitamin B(12) on cerebral ischemia rats was better than that of single folate.</p>

Induction of aryl hydrocarbon receptor and CYP1A1 mRNA by 2,3,7,8-tetrachlorodibenzo-p-dioxin in rat liver / 中华劳动卫生职业病杂志

<p><b>OBJECTIVE</b>To explore the toxic mechanism of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) by studying the induction of cytochrome P4501A1 (CYP1A1) and aryl hydrocarbon receptor (AHR) mRNA in liver of TCDD-treated SD rats.</p><p><b>METHODS</b>Thirty female SD rats were randomly divided into control group and 5 exposure groups, every group had 5 rats. The animals were treated i.p. with 0.01, 0.1, 1, 10, 50 microg TCDD/kg BW. AHR and CYP1A1 mRNA expression were analyzed by RT-PCR after 24 h.</p><p><b>RESULTS</b>The contents of AHR and CYP1A1 mRNA were increased in all exposure groups except the 0.01 microg TCDD/kg BW group. AHR mRNA content was significantly increased in 50 microg TCDD/kg BW group (P<0.05); CYP1A1 mRNA contents were significantly increased in all exposure groups (P<0.05) but not 0.01 microg TCDD/kg BW group. There were dose-response relationship between TCDD doses and AHR, CYP1A1 gene expression.</p><p><b>CONCLUSION</b>Both AHR and CYP1A1 gene in liver of TCDD-treated SD rats can be induced 24 h after exposure and CYP1A1 gene is more inducible than AHR gene.</p>