Formation of pyrrole adducts in 2,5-hexanedione-containing human serum cultured in vitro / 中华劳动卫生职业病杂志

<p><b>OBJECTIVE</b>To investigate the relationship between formation of pyrrole adducts and concentration of 2, 5-hexanedione (2, 5-HD) and to provide an experimental basis for the study on toxicity of n-hexane.</p><p><b>METHODS</b>Serum samples were collected from normal persons and were then filtered and sterilized. They were mixed with 2,5-HD to obtain sera with final 2, 5-HD concentrations of 10, 25, 50, 100, and 200 mg/L, and blank serum was also prepared. The sera were cultured at 37°C and taken at different time points. Colorimetry was used to quantify the pyrrole adducts formed in sera, and gas chromatography was used to measure the remaining 2, 5-HD levels in sera.</p><p><b>RESULTS</b>The content of pyrrole adducts increased as the culture proceeded and was dependent on the dose of 2, 5-HD; at the end of the experiment, the content of pyrrole adducts differed significantly across all concentration groups (P < 0.5). The concentrations of 2,5-HD decreased as the culture proceeded; at the end of the experiment, the concentrations of 2, 5-HD, from the highest to the lowest, decreased by 29%, 55%, 22%, 44%, and 40%, respectively. The decrease in 2, 5-HD had a positive correlation with the increase in pyrrole adducts, and the correlation coefficients for 200∼10 mg/L 2, 5-HD were 0.865, 0.697, 0.835, 0.823, and 0.814, respectively.</p><p><b>CONCLUSION</b>The content of formed pyrrole adducts increases as the concentration of 2,5-HD rises; there is a positive correlation between the decrease in 2, 5-HD and the increase in pyrrole adducts in human serum.</p>

Effect of docosahexaenoic acid and nervonic acid on the damage of learning and memory abilities in rats induced by 1-bromopropane / 中华劳动卫生职业病杂志

<p><b>OBJECTIVE</b>To investigate the protective effects of docosahexaenoic acid (DHA) and nervonic acid (NA) on the learning and memory abilities in rats exposed to 1-bromopropane (1-BP) and their action mechanisms.</p><p><b>METHODS</b>Forty male Wistar rats (specific pathogen-free) were randomly divided into 4 groups (n = 10 for each), i.e., solvent control group, 1-BP (800 mg/kg) group, NA (150 mg/kg) + 1-BP (800 mg/kg) group, and DHA (500 mg/kg) + 1-BP (800 mg/kg) group. The rats were given respective test substances by gavage for 7 d. The Morris water maze (MWM) test was performed from days 8 to 12 to evaluate the rats' learning and memory abilities. After MWM test, rats were sacrificed in the next day, and cerebral cortex was quickly dissected and homogenized in an ice bath. The supernatant of the obtained homogenate was collected to measure the content of glutathione (GSH) and malondialdehyde (MDA) and the activities of glutathione reductase (GR) and γ-glutamate cysteine ligase (γ-GCL).</p><p><b>RESULTS</b>The MWM spatial navigation test showed that the 1-BP group had significantly longer escape latency and significantly longer total swimming distance compared with the control group (P<0.05), while the DHA+1-BP group had significant decreases in escape latency and total swimming distance compared with the 1-BP group (P<0.05). The spatial probe test showed that the number of platform crossings was significantly greater in the DHA+1-BP group and NA+1-BP group than in the 1-BP group (P<0.05); compared with the control group, the 1-BP group had a significantly lower ratio of time spent in the zone around the platform to total time (P < 0.05), and the ratio was significantly higher in the DHA+1-BP group than in the 1-BP group (P < 0.05). Compared with the control group, the 1-BP group had a 18.1% decrease in GSH content, and DHA could significantly reverse 1-BP-induced decrease in GSH content (P < 0.05). Compared with the 1-BP group, the DHA+1-BP group and NA+1-BP group had significantly decreased MDA content (P < 0.05), the DHA+1-BP group had significantly increased GR activity (P < 0.05), and the NA+1-BP group had significantly increased γ-GCL activity (P < 0.05).</p><p><b>CONCLUSION</b>The rats exposed to 1-BP have oxidative stress in the brain and impaired cognitive function. DHA and NA can reduce 1-BP-induced cognitive function impairment in rats, possibly by increasing the activities of GR and γ-GCL and the content of GSH in the brain.</p>

Effect of 2,5-hexanedione on light-molecular-weight neurofilaments (NF-L) degradation of rat nerve tissues / 中华劳动卫生职业病杂志

<p><b>OBJECTIVE</b>To investigate the effect of 2,5-hexanedione (HD) on degradation of low-molecular-weight neurofilaments (NF-L) in nervous tissue of rats, and to explore the molecular mechanism of n-hexane neuropathy.</p><p><b>METHODS</b>Fifty male Wistar rats were randomly divided into one-week poisoning group (n = 10), two-week poisoning group (n = 10), three-week poisoning group (n = 10), four-week poisoning group (n = 10), and control group (n = 10). In the four poisoning groups, a rat model of n-hexane neuropathy was established by intraperitoneal injection of HD (400 mg/kg/d). The change in the sciatic nerve ultrastructure of each rat was observed under an electron microscope. The progression of HD-induced peripheral neuropathy was evaluated using a gait scoring system. The degradation rates of NF-L in the sciatic nerve and spinal cord of each rat were measured by Western Blotting.</p><p><b>RESULTS</b>The rats showed decrease in muscle strength and abnormal gait after two weeks of HD poisoning and mild or moderate paralysis after four weeks of HD poisoning. The sciatic nerve showed degenerative change, according to electron microscope observation. Compared with the control group, the two-week poisoning group, three-week poisoning group, and four-week poisoning group had the NF-L degradation rates decreased by 25.8%, 70.4%, and 69.7%, respectively, in the supernatant fraction of sciatic nerve, and by 14.7%, 64.6%, and 67.3%, respectively, in the sediment fraction of sciatic nerve, all showing a significant difference (P < 0.01). Compared with the control group, the one-week poisoning group had the NF-L degradation rate decreased by 33.87% in the supernatant fraction of spinal cord, the four-week poisoning group had the NF-L degradation rate increased by 16.2% in the supernatant fraction of spinal cord, and the one-week poisoning group and two-week poisoning group had the NF-L degradation rates decreased by 46.3% and 13.0% in the sediment fraction of spinal cord, all showing a significant difference (P < 0.01).</p><p><b>CONCLUSION</b>HD poisoning significantly inhibits NF-L degradation in the sciatic nerve, which may be associated with NF degeneration and accumulation in the axons of patients with n-hexane neuropathy.</p>

Changes in autophagy-related protein levels in nervous tissues of hens with tri-ortho-cresyl phosphate-induced delayed neuropathy / 中华劳动卫生职业病杂志

<p><b>OBJECTIVE</b>To study the changes in the levels of autophagy-related proteins, Atg1, Atg5, and Beclin1, in organophosphate-induced delayed neuropathy (OPIDN) caused by tri-ortho-cresyl phosphate (TOCP), and to investigate the molecular pathogenic mechanism of OPIDN.</p><p><b>METHODS</b>Thirty adult Roman hens were randomly and equally divided into control group and 1, 5, 10, and 21 d intoxication groups. Each hen in the intoxication group was administered TOCP by gavage at a single dose of 750 mg/kg, while each hen in the control group was administered the same volume of corn oil. The hens were killed at the corresponding time points, and their tibial nerves and spinal cords were collected. The levels of Atg1, Atg5, and Beclin1 in the tibial nerves and spinal cords were measured by immunoblotting.</p><p><b>RESULTS</b>Compared with those in the control group, the levels of Atg1 in tibial nerves decreased by 29.8%, 64.4%, 43.5%, and 19.8% at 1, 5, 10, and 21 d, respectively, after intoxication ((P < 0.05); the levels of Atg5 in tibial nerves decreased by 36.8%, 49.6%, 51.2%, and 31.5% at 1, 5, 10, and 21 d, respectively, after intoxication (P < 0.05); the levels of Beclin1 in tibial nerves decreased by 68.5%, 66.3%, and 32.2% at 1, 5, and 10 d, respectively, after intoxication (P < 0.05). Compared with those in the control group, the levels of Atg1 in spinal cords decreased by 23.5%, 48.7%, and 20% at 1, 5, and 10 d, respectively, after intoxication (P < 0.05); the levels of Atg5 in spinal cords decreased by 32.7%, 51.5%, 47.3%, and 39.6% at 1, 5, 10, and 21 d, respectively, after intoxication (P < 0.05); the levels of Beclin1 in spinal cords decreased by 28.9%, 50.2%, 43.2%, and 28.3% at 1, 5, 10, and 21 d, respectively, after intoxication (P < 0.05).</p><p><b>CONCLUSION</b>The intoxication of TOCP is associated with the significant changes in the levels of autophagy-related proteins in the nervous tissues of hens, which might be involved in the pathogenesis of OPIDN.</p>

Development of peripheral neuropathy rat model induced by 1-bromopropane / 中华劳动卫生职业病杂志

<p><b>OBJECTIVE</b>To observe the peripheral neurotoxicity of 1-bromopropane (1-BP) by developing an animal model of peripheral neuropathy through oral administration of 1-BP.</p><p><b>METHODS</b>Forty male Wistar rats were randomly and equally divided into low-dose group (200 mg/kg), medium-dose group (400 mg/kg), high-dose group (800 mg/kg), and control group. The rats in the low-dose, medium-dose, and high-dose groups were orally given 1-BP (dissolved in corn oil), while the rats in the control group were orally given an equal volume of corn oil. The oral administration (0.2 ml/100 g BW) was performed once per day, 5 days per week, for 16 consecutive weeks. Neurobehavioral indices including gait score, hindlimb grip strength, and hindlimb landing foot splay were recorded periodically. Hematological and biochemical parameters were also measured during and after 1-BP exposure.</p><p><b>RESULTS</b>The gait scores were significantly higher in the high-dose group (after 8 ∼ 16 weeks of 1-BP exposure), medium-dose group (after 14 ∼ 16 weeks of 1-BP exposure), and low-dose group (after 15 ∼ 16 weeks of 1-BP exposure) than in the control group (P < 0.05, P < 0.01). Compared with the control group, the high-dose group showed significantly decreased hindlimb grip strength after 9, 12, and 14 weeks of 1-BP exposure (P < 0.05, P < 0.01), with the hindlimbs paralyzed after 16 weeks of 1-BP exposure. After 16 weeks of 1-BP exposure, the hindlimb grip strengths of rats in the medium-dose and low-dose groups were decreased to 72.6% and 91.2% of the control value (P < 0.01, P < 0.05). Compared with the control group, the high-dose group showed significantly increased hindlimb landing foot splay after 12, 14, and 16 weeks of 1-BP exposure, and the medium-dose group showed significantly increased hindlimb landing foot splay after 14 and 16 weeks of 1-BP exposure (P < 0.05, P < 0.01). The high-dose and medium-dose groups showed significantly higher serum alanine aminotransferase (ALT) activity than the control group after 8 weeks of 1-BP exposure, and so did the low-dose group after 16 weeks of 1-BP exposure (P < 0.01).</p><p><b>CONCLUSION</b>The nervous system is sensitive to the toxic effect of 1-BP, and 1-BP exposure can induce peripheral neuropathy in rats.</p>

Effects of garlic oil, age and sex on n-hexane metabolism in rats / 中华劳动卫生职业病杂志

<p><b>OBJECTIVE</b>To investigate effects of garlic oil (GO), age and sex on n-hexane metabolism in rats.</p><p><b>METHODS</b>The Wistar rats were used as experimental animals. (1) Intragastric administration: n-hexane group (3000 mg/kg n-hexane), GO treated group (80 mg/kg GO ig. an hour earlier than 3000 mg/kg n-hexane), then blood was taken from tails of rats at 8, 12, 16, 20, 24, 28, 32 h points after n-hexane administration. (2) Intraperitoneal injection: n-hexane group (1000 mg/kg n-hexane), GO treated group (80 mg/kg GO ig. an hour earlier than 1000 mg/kg n-hexane), then took blood was taken from tails of rats at 8, 12, 16, 20, 24, 28 h points after n-hexane injection. (3) 7 rats each group of 6, 8, 10 weeks age were administrated by 3000 mg/kg n-hexane intragastrically, then were taken blood from tails at 16, 20, 24 h points after administration. (4) 7 male and 7 female rats of 8 weeks age were administrated by 3000 mg/kg n-hexane intragastrically, then were taken blood from tails at 16, 20, 24, 28 h points after administration. The gas chromatography was used to determine the metabolite 2, 5-hexanedione concentration of n-hexane in serum and 2, 5-hexanedione concentration was compared between GO and no GO treated rats, different ages and different sexes.</p><p><b>RESULTS</b>(1) Intragastric administration: 2, 5-hexanedione concentrations in serum of n-hexane group and GO treated group had the peak 19.2 and 12.3 µg/ml at 20h and 24 h points. Compared with n-hexane group, the serum 2, 5-hexanedione concentration of GO treated group was lower at time points prior to peak and 2, 5-hexanedione eliminating process was slower after peak. (2) Intraperitoneal injection: effects of GO on the serum 2, 5-hexanedione concentrations was very similar to intragastric administration, 2, 5-hexanedione concentrations in serum of n-hexane group and GO treated group had the peak 15.0 and 6.7 µg/ml at 12 h and 16 h points. (3) Comparison of the serum 2, 5-hexanedione concentrations of different weeks age rats: The serum 2, 5-hexanedione concentrations of 6, 8, 10 weeks age rats were 25.5, 15.0, 12.8 µg/ml each (8, 10 weeks age significantly lower than 6 weeks age) at 16 h point; at 20 h point, they were 24.7, 18.3, 15.0 µg/ml each (10 weeks age significantly lower than 6 weeks age); at 24 h point, they were 11.0, 14.7, 8.1 µg/ml each (10 weeks age significantly lower than 8 weeks age). (4) Comparisons of the serum 2, 5-hexanedione concentrations of different sex rats: the serum 2, 5-hexanedione concentrations of male and female rats were 22.5, 17.2 µg/ml each at 16 h point (different significantly); at 20, 24, 28 h points, they were 27.6, 22.9 µg/ml, 24.6, 19.1 µg/ml, 19.1, 13.8 µg/ml each (different non-significantly).</p><p><b>CONCLUSION</b>GO reduces production of 2, 5-hexanedione in serum generated by n-hexane in rats; the metabolic capacity of low age rats on n-hexane is stronger than high age ones.</p>

The effects of tea polyphenols on the injury of fibrinolytic functions induced by high-methionine dietary in rats / 中华预防医学杂志

<p><b>OBJECTIVE</b>To study the protective impact of tea polyphenols (TP) on the injury of fibrinolytic functions induced by high-methionine dietary in rats.</p><p><b>METHODS</b>50 male Wistar rats were divided by stratified based on body weight into 5 groups with 10 in each group: namely control group, model group, low-dose TP group, medium-dose TP group and high-dose TP group. The rats in model group and TP groups were fed with 3% methionine dietary, control group rats with routine diet. In addition, rats in low-dose, medium-dose and high-dose TP groups were treated with TP at 50, 100 and 200 mg/kg dosage respectively by gavages every day, control group and model group rats were given with same amount distilled water. The animals were sacrificed after 8 weeks. The levels of tissue-type plasminogen activator (t-PA) and type-1 plasminogen activator inhibitor (PAI-1) in plasma were determined by ELISA assays, mRNA levels of t-PA and PAI-1 in aortic arch were detected by RT-PCR, t-PA and PAI-1 expression in aortic arch were detected by immunohistochemistry strept-avidin-biotin complex (SABC).</p><p><b>RESULTS</b>After experiment, the t-PA expression of aortic arch in control group, model group, low-dose TP group, medium-dose TP group and high-dose TP group were 133.03 ± 10.14, 95.46 ± 11.08, 111.97 ± 11.91, 130.23 ± 10.80, 139.39 ± 9.41 (F = 14.15, P < 0.01), respectively, and the PAI-1 expression were 90.91 ± 8.67, 166.76 ± 12.18, 139.63 ± 12.71, 134.66 ± 13.19, 109.49 ± 10.82 (F = 31.44, P < 0.01). The t-PA concentration of plasma were (10.69 ± 1.26), (6.13 ± 0.92), (8.56 ± 1.19), (9.69 ± 0.92), (11.97 ± 1.08) ng/ml, respectively (F = 41.98, P < 0.01), and the PAI-1 concentration of plasma were (6.31 ± 0.81), (16.98 ± 1.27), (11.39 ± 0.82), (8.46 ± 0.67), (8.08 ± 0.91) ng/ml, respectively (F = 207.74, P < 0.01). The mRNA levels of t-PA in aortic arch were 1.12 ± 0.02, 0.75 ± 0.14, 1.01 ± 0.09, 0.95 ± 0.08, 1.05 ± 0.13 (F = 5.77, P < 0.05), and the mRNA levels of PAI-1 in aortic arch were 1.25 ± 0.11, 1.74 ± 0.06, 1.23 ± 0.05, 1.09 ± 0.14, 1.23 ± 0.04 (F = 23.56, P < 0.01).</p><p><b>CONCLUSION</b>The results indicate that TP seems to have regulatory function on transcription and protein levels of t-PA and PAI-1, in addition to maintaining the balance between PAI-1 and t-PA and healing the injury of fibrinolytic functions in rats induced by high-methionine dietary.</p>

Protective effects of garlic oil on n-hexane-induced neurotoxicity in rats via inhibition of hepatic alcohol dehydrogenase activity / 中华劳动卫生职业病杂志

<p><b>OBJECTIVE</b>To study the protective effects of garlic oil (GO) on the peripheral nerve injuries induced by n-hexane.</p><p><b>METHODS</b>Male Wistar rats were randomly divided into four groups (10 rats in each group): the control, the n-hexane treatment (2000 mg/kg), the low dose GO, and the high dose GO groups. The rats in the low and high doses of GO groups were pretreated with GO (40 and 80 mg/kg) before exposure to n-hexane (2000 mg/ kg), while the animals of the n-hexane treatment group were given normal saline and then 2000 mg/ kg n-hexane. The rats were exposed to GO and n-hexane 6 times a week for 10 weeks. The gait scores and staying time on the rotating rod for all rats were detected every two weeks. The rats were sacrificed at the end of ten weeks, then the levels of alcohol dehydrogenase (ADH), maleic dialdehyde (MDA), reduced glutathione (GSH), glutathione peroxidase(GSH-Px), total antioxidation capacity(T-AOC) and the ability of inhibition of *OH in livers were examined.</p><p><b>RESULTS</b>The gait scores increased significantly and the time staying on the rotating rod obviously decreased in rats of n-hexane treatment group, as compared with control group (P < 0.05 or P < 0.01). In the hepatic tissues of n-hexane group, the levels of MDA and ADH significantly increased, the activities of GSH-Px, T-AOC and the ability of inhibition of *OH obviously decreased, as compared to control group (P < 0.05 or P < 0.01). In 2 GO groups, the gait scores and the staying time on the rotating rod were significantly improved, the levels of MDA and ADH significantly decreased, the activities of GSH-Px, T-AOC and the ability of inhibition of *OH obviously increased, as compared with n-hexane group (P < 0.05 or P < 0.01 ).</p><p><b>CONCLUSION</b>ADH could play an important role in the protective effects induced by garlic oil on the peripheral nerve injuries produced by n-hexane.</p>

Effects of 1-bromopropane exposure on cognitive function in rats / 中华劳动卫生职业病杂志

<p><b>OBJECTIVE</b>To study the effects of 1-bromopropane (1-BP) on the functions of learning-memory and the central cholinergic system in rats.</p><p><b>METHODS</b>Forty male Wistar rats were randomly divided into four groups: low 1-BP group (200 mg/kg), middle 1-BP group (400 mg/kg), high 1-BP group (800 mg/kg) and control group, and the exposure time was 7 days. The Morris water maze (MWM) test was applied to evaluate the learning-memory function in rats. After the MWM test, the rats were sacrificed, the cerebral cortex and hippocampus were quickly dissected and homogenized in ice bath. The activity of acetylcholine esterase (AChE) and choline acetyltransferase (ChAT) in supernatant of homogenate were detected.</p><p><b>RESULTS</b>The latency and swim path-length of rats in middle and high 1-BP groups prolonged significantly in place navigation test and the efficiency of searching strategy obviously decreased, as compared with control group (P < 0.05 or P < 0.01). In spatial probe test, the number of crossing platform in three 1-BP groups decreased significantly, as compared with control group (P < 0.05 or P < 0.01). The cortical AChE activity of rats in middle and high 1-BP groups was significantly higher than that of control and low 1-BP group (P < 0.05 or P < 0.01). The AChE activity in rat hippocampus of high 1-BP group obviously increased, as compared with control group as compared with control group (P < 0.05). There was no significant difference of cortical ChAT activity between three 1-BP groups and control group (P > 0.05). In the hippocampus, there was no difference of ChAT activity among the groups (P > 0.05).</p><p><b>CONCLUSION</b>1-BP exposure could significantly influence the learning-memory function in rats due to the increase of AChE activity.</p>

The role of CYP2E1 in the protection of garlic oil's from n-hexane-induced neurotoxicity / 中华劳动卫生职业病杂志

<p><b>OBJECTIVE</b>To study the role of CYP2E1 in the protective effects and mechanism of garlic oil (GO) on the peripheral nerve injuries induced by n-hexane.</p><p><b>METHODS</b>Fifty male Wistar rats were randomly divided into five groups (n = 10): the control, the GO (80 mg/kg) control, the n-hexane (2000 mg/kg) model, the low dose GO (40 mg/kg) plus n-hexane, and the high dose GO (80 mg/kg) plus n-hexane groups. All rats were treated by intragastric administration 6 times a week for 10 weeks. The gait scores were determined every two weeks for monitoring the peripheral neurotrosis. All rats were sacrificed in 10 weeks, the activities and expression levels of hepatic CYP2E1 and 2, 5-HD in serum were examined.</p><p><b>RESULTS</b>As compared with control group, the content and activity of hepatic CYP2E1 in GO control group reduced by 83.1% and 48.3% respectively (P < 0.01), the content and activity of hepatic CYP2E1 in model group increased by 112.5% and 72.2% respectively (P < 0.01). As compared with model group, the contents of hepatic CYP2E1 in low dose and high dose GO groups reduced by 32.9% and 39.1% respectively, the activities of hepatic CYP2E1 in low dose and high dose GO groups reduced by 27.4% and 44.5% respectively (P < 0.01); the contents of serum 2,5-HD in low dose and high dose GO groups reduced by 47.7% and 78.7% respectively (P < 0.01). The gait scores in model, low dose and high dose GO groups were significantly lower than that in control group, but the gait scores in low dose and high dose GO groups were significantly lower than that in model group (P < 0.05).</p><p><b>CONCLUSION</b>Garlic oil can effectively reduce the peripheral neurotrosis induced by n-hexane due to the decreased content and activity of hepatic CYP2E1, resulting in the reduced formation of 2, 5-HD from n-hexane.</p>

Effect of carbon disulfide on expression of matrix metalloproteinase-2 and metalloproteinase-9 in embryo and uterus of pregnant mice / 中华劳动卫生职业病杂志

<p><b>OBJECTIVE</b>To observe the effect of carbon disulfide (CS(2)) on the expression of matrix metalloproteinase (MMP)-2, MMP-9 in mouse embryo and uterus tissues and to explore the mechanism of embryo toxicity induced by CS(2).</p><p><b>METHODS</b>At the phases of follicular development and embryonic implantation which was subdivided into early-implantation phase and late-implantation phase, mice were intraperitoneally exposed to CS(2) (the dosage was 631.4 mg/kg, and the volume was 0.1ml/10 g body weight) for 2 consecutive days. All indicators were got at the ninth day in gestation, and the expression of MMP-2 and MMP-9 in embryo and uterus tissues was analyzed by gelatin zymography.</p><p><b>RESULTS</b>The number of implanted embryos significantly decreased after exposure at late-implantation phase (16.000 ± 12.166) compared with those of the control (30.700 ± 5.599, P < 0.05). Expression of MMP-2 and MMP-9 in embryos declined obviously at the three reproductive phases (P < 0.01), and the levels of MMP-2 and MMP-9 expression in embryos at the phases of late-implantation phase (0.6837 ± 0.0929, 0.7309 ± 0.0822) and follicular development (0.6222 ± 0.0997, 0.7520 ± 0.1068) were much lower than those of the control (1.0000 ± 0.0710, 1.0000 ± 0.0413, P < 0.01). Expression of MMP-2 and MMP-9 in uterus significantly increased at the phase of late-implantation (1.3153 ± 0.3032, 5.0210 ± 4.0307) compared with those of the control (1.0000 ± 0.1771, 1.0000 ± 0.0996, P < 0.01).</p><p><b>CONCLUSION</b>Embryo toxicity of CS(2) is more obvious at the phase of late-implantation. Exposure to CS(2) disturbs expression of MMP-2 and MMP-9 in embryo and uterus tissues, which might be one of the important factors contributed to embryo toxicity induced by CS(2).</p>

Effect of phenylmethylsulfonyl fluoride pretreated on neurofilament subunits in spinal cords of hens administrated with tri-o-cresyl phosphate / 中华劳动卫生职业病杂志

<p><b>OBJECTIVE</b>To investigate the dynamic changes of neurofilaments (NFs) proteins in spinal cords of hens with phenylmethylsulfonyl fluoride (PMSF) pretreatment for exploring the mechanism of tri-o-cresyl phosphate (TOCP)-induced delayed neuropathy (OPIDN).</p><p><b>METHOD</b>Adult Roman hens were randomly divided into three groups, control, TOCP and PMSF + TOCP. Birds in PMSF + TOCP set were pretreated with PMSF, 24 hours later, hens in both TOCP group and PMSF + TOCP group were administrated with TOCP at a single dosage of 750 mg/kg. Then all animals were sacrificed on the corresponding time-points of 1, 5, 10, and 21 days respectively after dosing of 750 mg/kg TOCP. The spinal cords were dissected, homogenized, and centrifuged at 100,000 x g. The levels of high molecular neurofilament (NF-H), medium molecular neurofilament (NF-M) and low molecular neurofilament (NF-L) in both pellet and supernatant fractions of spinal cords were determined by SDS-PAGE and Western-blotting.</p><p><b>RESULTS</b>The hens in TOCP group showed paralysis gait at the end of 21-day experimental period. The levels of NFs proteins in spinal cords changed obviously. Compared with control, the NFs in pellet showed a dramatic decrease on day 10 and then followed by a recovery. In the supernatant, the NFs proteins showed similar changes, which decreased significantly on day 10 and almost recovered control on day 21. Such as, NF-L, NF-M and NF-H decreased by 51%, 86% and 38% on day 10. The OPIDN signs were not observed in PMSF + TOCP group, and imbalances of NFs were obviously alleviated. Compared with control, only NF-M in pellet increased by 21% (P < 0.05) on day 21, others remained no changes; The levels of NF-H and NF-M in supernatant respectively increased by 19% and 35% on day 21, others were no significant statistical differences.</p><p><b>CONCLUSION</b>TOCP may induce imbalance of NFs levels in progress of OPIDN, and PMSF pretreatment may protect animals from OPIDN by reducing above changes, which may explain that TOCP-induced imbalance of NFs may be connected with the occurrence and development of OPIDN.</p>

Effects of tacrolimus (FK506) on heat-shock proteins 70, Bcl-2 and Bax expression in nervous tissue of acrylamide-induced rat / 中华劳动卫生职业病杂志

<p><b>OBJECTIVE</b>To investigate the effects of tacrolimus (FK506) on behavioral function and heat-shock proteins (HSP70) expression in nervous tissues of acrylamide (ACR)-induced rats.</p><p><b>METHODS</b>Totally 40 health Wistar rats were randomly divided into control group, model group, low and high doses of FK506 groups. All four groups were treated five times per week for four weeks. Gait score was measured every week. And rats were sacrificed on day 28, the cerebrum, spinal cord and sciatic nerve were dissected, and homogenized in ice bath, then the levels of HSP70 and Bcl-2, Bax were analyzed by western bloting.</p><p><b>RESULTS</b>Compared with the ACR model group, the gait score in low and high doses of FK506 groups decreased by 30.1% and 47.7% respectively in the 4th week. In the cerebrum and sciatic nerve pellet, the level of HSP70 in the FK506 groups increased by 11.6%, 33.3% and 56.3%, 58.5% (P < 0.01), but no significant changes existed in spinal cord. The level of Bcl-2 in the sciatic nerve pellet increased by 39.1% (P < 0.01) but no significant changes existed in the cerebrum and spinal cord from low dose of FK506 group. And the level of Bax in the spinal cord pellet markedly increased by 46.8% but not in cerebrum and sciatic nerve pellet; Whereas in the tissues mentioned above, the levels of Bcl-2 were enhanced remarkably by 16.3%, 14.8% and 56.0% (P < 0.01) in the high dose of FK506 group. And the level of Bax in the cerebrum and spinal cord pellet markedly increased by 16.4% and 40.2% but not in sciatic nerve. The values of Bcl-2/Bax in low and high doses of FK506 groups clearly increased by 15.9%, 33.3%, 36.9% and 30.1%, 49.1%, 60.1% (P < 0.01).</p><p><b>CONCLUSION</b>The administration of FK506 has dramatically neuroprotective effects against the development of ACR neuropathy, which may be related to up-regulating the expression of HSP70 and Bcl-2 with down-regulating the expression of Bax.</p>

Protective effect of garlic oil given at different time against acute liver injury induced by CCl4 / 中华劳动卫生职业病杂志

<p><b>OBJECTIVE</b>To observe and compare the protective effect of garlic oil against carbon tetrachloride (CCL)-induced acute liver injury.</p><p><b>METHODS</b>The experiments include 4 preventive groups and 2 therapeutic groups. In every preventive and therapeutic group, the mice were randomized into 6 groups with 15 each, including one negative control group, one solvent control group, one CCl4 model group and 3 garlic oil groups (25, 50, and 100 mg/kg body weight). Before given a single gavage of CCl4 (80 mg/kg), the mice were pretreated with garlic oil by gavage in preventive group 1 (30 days, once daily), preventive group 2 (5 days, once daily), preventive group 3 (ahead of 2 h, once), preventive group 4 (immediately, once) or the vehicle (corn oil, 10 ml/kg) in solvent control group. In therapeutic groups, the mice were gavaged garlic oil 2 h (once, in therapeutic 1) or for 5 days (once daily, in therapeutic 2) after administration CCl. After 24 h of the last administration, blood was collected and centrifuged at 2500 r/min at 4 degrees C for 10 min, and serum was removed to measure ALT and AST activities. The liver was dissected, weighed to calculate the liver coefficient (relative liver weight). At the same time, the liver samples were studied by histological examinations.</p><p><b>RESULTS</b>Compared with negative group, the liver coefficient and the activities of ALT and AST in serum of model group were increased remarkably (P < 0.01). Compared with CCl model group, the liver coefficient and the activities of ALT and AST in serum were decreased significantly (P < 0.01) by garlic oil dose-dependently in each preventive group. Simultaneously, histological assessment showed that garlic oil effectively alleviated hepatocyte injuries induced by CCl4. Comparing the preventive effects of garlic oil in every group, it was better in preventive group 3 than others. However, all indexes and histological examinations in therapeutic group 1 did not show the difference with those of CCl4 model group. In therapeutic group 2, all indexes recovered after 5 d of CCl4 administration.</p><p><b>CONCLUSIONS</b>Garlic oil can prevent acute liver injury induced by CCl4 and the effect is better in ahead of 2 h group than others.</p>

Effects of garlic oil on n-hexane metabolized to 2, 5-hexanedione in mice serum / 中华劳动卫生职业病杂志

<p><b>OBJECTIVE</b>To investigate the effects of garlic oil (GO) on n-hexane metabolized to 2, 5-hexanedione (2, 5-HD) in mice.</p><p><b>METHODS</b>Adult healthy Kunming-mice were treated with n-hexane and GO. The serum was obtained and extracted with ethyl acetate, and the levels of the serum 2, 5-HD were determined by gas chromatography.</p><p><b>RESULTS</b>(1) The concentration of 2, 5-HD in serum increased firstly after a single exposure to n-hexane (4 000 mg/kg). The peak value occurred at 10 hours after n-hexane treatment, but could hardly be detected at 20 h. (2) There was no 2, 5-HD in serum of control mice. The content of 2, 5-HD in serum increased along with the exposure dose of n-hexane. The serum 2, 5-HD contents of the 2000, 4000 and 6000 mg/kg groups mice were 8.04, 16.68 and 22.38 microg/ml at 8 h in pretreated mice, respectively, and showed significant dose-effect relationship. (3) When the different age mice were exposed to the same dose of n-hexane, the contents of 2, 5-HD in serum were significantly different after 8 hours (P<0.05). The serum 2, 5-HD level of the 5 weeks old mice (22.83 microg/ml) was much higher than the 4 (19.59 microg/ml) and 6 (16.42 microg/ml) weeks old mice. (4) When the different gender mice were exposed to the same dose of n-hexane, the concentration of 2, 5-HD in serum of female mice (13.22 microg/ml) was higher than that of the female mice (10.34 microg/ml, P<0.05). (5) GO significantly inhibited the increase of the serum 2, 5-HD levels of both the pretreatment and post-treatment groups treated with 80 mg/kg n-hexane respectively, but the pretreatment with GO exhibited the more suppressive effects than the post-treatment (P>0.05). Compared with the n-hexane group, the concentrations of serum 2, 5-HD in GO-pretreated groups mice decreased by 16.2%, 20.8%, 22.8% (P<0.05) and 32.1% (P<0.01), respectively, and showed significant dose-effect relationship.</p><p><b>CONCLUSION</b>The serum content of 2, 5-HD, the metabolite of n-hexane, is different in different genders and age mice after exposed to the same dose of n-hexane. GO can effectively inhibit the production of n-hexane metabolized to 2, 5-HD in mice serum.</p>

Dynamic study of neurofilament contents in rat's spinal cord induced by 2, 5-hexanedione / 中华劳动卫生职业病杂志

<p><b>OBJECTIVE</b>To investigate the dynamic changes of neurofilament contents in rat's spinal cord induced by 2, 5-hexanedione (2, 5-HD), and explore the molecular mechanism of n-hexane neuropathy.</p><p><b>METHODS</b>Male Wistar rats were administered at a dosage of 400 mg/kg/day 2, 5-HD for 2, 4 and 8 weeks respectively. HD-induced neurological defects were detected and quantified using gait score, and the relative lev-els of NF-H, NF-M, and NF-L in spinal cords of rats were determined by Western Blotting.</p><p><b>RESULTS</b>Exposure to 2, 5-HD produced progressive gait abnormalities, which suggested that the rat model of 2, 5-HD-induced neurotoxicity was established successfully. Western-Blotting results showed that NFs content in spinal cord demonstrated a progressive decline as the intoxication continued. In the supernatant fraction, compared to the controls, NF-H con-tent decreased by 15.7%, 57.0%, and 58.0% respectively after 2, 4, and 8-week treatment with 2, 5-HD (P < 0.01); accordingly, NF-M decreased by 36.0%, 61.3%, and 65.2% respectively (P < 0.01); NF-L decreased by 20.8%, 43.9%, and 44.3% respectively (P < 0.01). In the pellet fraction, the contents of NF-H in groups of 4 and 8 weeks' exposure to HD decreased by 35.6% and 43.2%, respectively (P < 0.01), and those of NF-L decreased by 26.4% and 42.1%, respectively (P < 0.01) when compared to the control. Further-more, NF-M contents in groups of 2, 4 and 8 weeks' exposure decreased by 23.3%, 33.9%, and 63.7% respectively (P < 0.01). The NFs level in spinal cords was highly correlated with gait abnormality of treated rats as the intoxication went on. Multiple correlation coefficients of NF-H, NF-M, and NF-L content with gait score of HD-treated rat were 0.8912, 0.9282 and 0.8981 (P < 0.01) respectively.</p><p><b>CONCLUSION</b>The declines of NFs are high-ly related to neurobehavioral abnormality of 2, 5-HD-treated animals, and involved in the development of n-hexane neuropathy.</p>

Effects of garlic oil on 2, 5-HD induced lipid peroxidation damage in rat nerve tissues / 中华劳动卫生职业病杂志

<p><b>OBJECTIVE</b>To investigate the effects of garlic oil (GO) against the peroxidation damage of rat nerve tissue and the peripheral motor neuropathy induced by 2, 5-HD.</p><p><b>METHODS</b>Male Wistar rats were divided into four groups, with 10 in each group. The model group, and low and high doses of GO groups were administrated with 2, 5-HD (ip, 300 mg/kg), respectively; The control group was treated with sodium chloride, five times per week for six weeks. Pretreatment with GO gavaged (40 mg/kg or 80 mg/kg) started one week be-fore 2, 5-HD treatment, and lasted to the end of the experiment. Neurobehavioral indexes were examined at the zero, second and fourth week. At the end of the experiment, the scores of the gait, and the concentration of MDA and GSH, the level of TAOC and the ability of inhibition of.OH in cerebrum, spinal cord and sciatic nerve were examined.</p><p><b>RESULTS</b>Compared with the zero week, except of the control group rats, the hind limb landing foot splay of three groups rats decreased by 44%, 50% and 49% at the fourth week, respectively without significant difference. The threshold value of balance in model, GO low and high doses groups rats decreased by 30%, 45% and 68% at the fourth week, respectively, and lower than the control group rats (P < 0.01). GO low and high doses groups rats showed the serious abnormality at the fourth week, before one week of the model group rats. The scores of gait of model, and GO low and high doses groups rats increased significantly compared with control group rats, and the GO high dose group rats were higher than model group rats (P < 0.05). Increase of the concentration of MDA, and decrease of the level of the ability of inhibition of.OH were induced by 2, 5-HD in cerebrum, spinal cord and sciatic nerve. The concentration of MDA increased, and the level of the ability of inhibition of.OH decreased (P < 0.05 or P < 0.01), respectively. The results showed that the concentration of MDA decreased, and the level of the ability of inhibition of.OH induced by GO in cerebrum, spinal cord and sciatic nerve increased, the concentration of MDA of GO low doses group rats decreased, the level of the ability of inhibition of.OH increased, the concentration of MDA of GO high doses group rats decreased (P < 0.01) respectively, and the level of the ability of inhibition of.OH increased (P < 0.01) in nerve tissue.</p><p><b>CONCLUSION</b>GO has antagonist effect on the 2, 5-HD induced peroxidation damage, but can not improve the function of the peripheral motor nerve, indicating that the lipid peroxidation does not play an important role in 2, 5-HD neurotoxicity.</p>

Expression changes of cyclin dependent kinase 5/p35 in nerve tissues of 2, 5-hexanedione intoxicated rats / 中华劳动卫生职业病杂志

<p><b>OBJECTIVE</b>To explore the role of cyclin dependent kinase 5 (CDK5) in 2, 5-hexanedione (HD)-induced neuropathy.</p><p><b>METHODS</b>Thirty male Wistar rats weighted 200 approximately 240 g were divided randomly into three groups, i.e. control group, 200 mg/kg HD group and 400 mg/kg HD group (n = 10 for each group). HD was administered to rats by intraperitoneal injection at dosage of 200 or 400 mg/kg for 8 weeks (five times per week) to establish the intoxicated rats model. The relative contents of CDK5, p35 and p25 were determined in cerebrum, spinal cord and sciatic nerve of rats by Western Blotting.</p><p><b>RESULTS</b>Compared with that of the control group rats, p35 contents were significantly decreased (P < 0.01) in the cytosolic fractions of cerebrum and spinal cord in both the 200 and 400 mg/kg HD intoxicated rats, while in the membrane fractions of spinal cord and sciatic nerve, p35 contents were increased significantly (P < 0.01). The changes of p25 showed the same pattern with p35. P25 contents were significantly reduced (P < 0.05) in the cytosolic (cerebrum and spinal cord) and membrane (cerebrum) fractions of both HD-treated rats and were elevated (P < 0.01) in the membrane fraction of spinal cord and cytosolic fraction of sciatic nerve. The relative amounts of CDK5 were significantly decreased (P < 0.01) in the cytosolic and membrane fractions of cerebrum in both the 200 and 400 mg/kg HD intoxicated rats. Except for membrane fraction of sciatic nerve, the significant increased (P < 0.01) of CDK5 were observed in the spinal cord and sciatic nerve of both the 200 and 400 mg/kg HD treated rats.</p><p><b>CONCLUSION</b>HD can induce significant changes of CDK5 and its activators p35, p25 in nerve tissues, which may be related to the neuropathy induced by HD.</p>

Alterations of microtubule and microfilament expression in spinal cord of carbon disulfide intoxicated rats / 中华劳动卫生职业病杂志

<p><b>OBJECTIVE</b>To investigate whether the alterations of microtubule and microfilament expression are responsible for the neurotoxicity of carbon disulfide.</p><p><b>METHODS</b>Wistar rats were administered with carbon disulfide by gavage at a dosage of 300 or 500 mg/kg for continuous 12 weeks (five times per week). Spinal cords of carbon disulfide-intoxicated rats and their age-matched controls were Triton-extracted and ultracentrifuged to yield a pellet and a corresponding supernatant fraction. Then, the contents of alpha-tubulin, beta-tubulin, and beta-actin in both fractions were determined by immunoblotting. In the meantime, their mRNA levels in spinal cords were quantified using reverse transcriptase-polymerase chain reaction (RT-PCR).</p><p><b>RESULTS</b>In the supernatant fraction, the contents of beta-tubulin and beta-actin in both treated groups increased significantly (P < 0.01) the content of beta-tubulin increased by 141% and 158% respectively, and the content of beta-actin increased by 19% and 32% respectively. In the pellet fraction, the content of beta-tubulin in both groups increased by 107%(P < 0.01) and 118%(P < 0.01) respectively, and the others keep unaffected. In the meantime, the levels of of mRNA expression of beta-tubulin and beta-actin gene were elevated consistently in CS(2)-treated groups (P < 0.01) the levels of mRNA expression of beta-tubulin increased by 207% and 212% respectively, and the levels of mRNA expression of beta-actin increased by 94% and 91% respectively.</p><p><b>CONCLUSION</b>Carbon disulfide intoxication results in alternations of microtubule and microfilament expression, and the alternations might be related to its neurotoxicity.</p>

The subchronic toxicity study on the biological amnion / 中国医疗器械杂志

As the new type cornea ulcer renovation material, the biological amnion is to be implanted into the human body for a long time, a subchronic toxicity study in rats is made to evaluate its possibility of subchronic toxicity. The study is based on the requirements of "Biological Evaluation of Medical Devices, Part 11: Tests for systemic toxicity and Part 6: Tests for local effects after implantation". After the implantation of examples to be tested, animals were observed daily for mortality and 92 days later the possible subchronic toxicity was evaluated. And a necropsy was conducted and the selected organs were excised, weighed, and processed histologically. Body weights, organ weights, organ/body weight ratios, hematology values and clinical chemistry values were analyzed statistically. Results show that daily clinical observation, body weights, necropsy findings, organ weights and organ/body weight ratios were within acceptable limits in test and control treatment groups. There were no obvious changes in histopathology, hematology values or clinical chemistry values in either male or female rats and no notable differences between the biological amnion and the control amnion. This study proves that, the cornea ulcer renovation material, the biological amnion does not induce subchronic toxicity.