RESUMO
OBJECTIVE: To explore the influencing factors of occupational stress from occupational hazards in employees of a power grid enterprise. METHODS: A total of 972 employees from 3 substations and 1 power dispatch center of a power grid enterprise were selected as research subjects by the cluster sampling method. The Chinese version of the Job Content Questionnaire was used to evaluate the occupational stress using the job demand control(JDC) model. The influence of occupational hazards on occupational stress was analyzed. RESULTS: The median, the 25 th and 75 th percentile scores [M(P_(25), P_(75))] of the 972 research subjects on job demand, job control, and social support dimensions of JDC model occupational stress were 14(12, 15), 25(23, 26), 24(23, 24), respectively. The M(P_(25), P_(75)) of the demand/control(D/C) ratio was 0.99(0.89, 1.13). The incidence of occupational stress was 48.4%(470/972) by the JDC model. The job demand dimension scores, D/C ratios, and incidence of occupational stress by JDC model were higher in employees exposed to electromagnetic radiation, high temperature, high altitude, and visual display terminal(VDT) than in those employees not exposed to the above factors(all P<0.05). The results of multivariate logistic regression analysis showed that the risk of occupational stress increased in those employees exposed to high temperature, high altitude and VDT(all P<0.05) after excluding the influence of confounding factors such as age, length of service, monthly income and exercise. The odds ratio and 95% confidence intervals were 1.91(1.43-2.54) and 1.67(1.26-2.21), respectively. CONCLUSION: The level of occupational stress among employees in power grid enterprise is relatively high by JDC model. High-temperature, high-altitude and VDT operation are the main risk factors of occupational stress by JDC model.
RESUMO
OBJECTIVE: To investigate the effect of n-hexane on the level of sex hormones and expression of estrogen receptor(ER) in rats and the protective effect of Lyciumbarbarum polysaccharide(LBP) on n-hexane-induced reproductive toxicity. METHODS: Based on factorial design model of 4×2, specific pathogen free adult female SD rats were divided into control group and low-, medium-and high-n-hexane exposure groups, and each group was divided into non-LBP intervention and LBP intervention sub-group. There were 8 subgroups with 6 rats in each group. On the first day, the rats in the 4 groups were given intraperitoneal injection of n-hexane at 0, 675, 1 350 and 2 700 mg/kg body weight, respectively. On day 2-4, the rats in the non-LBP intervention subgroup were given intragastric administration of 0.9% sodium chloride solution, and the rats in the LBP intervention subgroup were given intragastric administration of LBP at 50 mg/kg body weight once a day. On the fifth day, all animals were sacrificed, and the levels of follicle stimulating hormone(FSH), luteinizing hormone(LH), estradiol, progesterone were detected by enzyme linked immunosorbent assay. The mRNA expression of Erα, Erβ and G protein coupled estrogen receptor 1(Gper1) was detected by real time fluorescence polymerase chain reaction, and the expression of ERα, ERβ and GPER1 protein was detected by Western blotting. RESULTS: i) In the absence of LBP intervention(i.e. simple n-hexane exposure), there was no significant difference in the level of serum FSH, LH, estradiol and progesterone in the 4 groups(P>0.05). The relative expression of Erβ mRNA in ovary of low dose group decreased, while the relative expression of proteins of ERα and GPER1 increased(P<0.05) when compared with the control group. The relative expression of Erα mRNA and GPER1 protein in the ovary of medium-and high-dose groups increased(P<0.05), while the relative expression of Erβ, Gper1 mRNA and ERβ protein decreased(P<0.05). The relative expression of ERα protein in ovary of high-dose group increased(P<0.05). ii) At the same dose of n-hexane exposure, the relative expression of Erα mRNA in ovary of rats in low dose group increased(P<0.05), while the relative expression of ERβ and GPER1 protein decreased in LBP intervention group compared with the no LBP intervention group(P<0.05). The relative expression of ERα and GPER1 protein in ovary of medium dose group increased(P<0.05), while the relative expression of Gper1 mRNA and GPER1 protein in ovary of high dose group decreased in LBP intervention group compared with the no LBP intervention group(P<0.05). CONCLUSION: n-Hexane can up-regulate the expression of ERα and GPER1 in rat ovary, but has no significant effect on female endocrine system. LBP may play a protective role in female reproductive system by up-regulating the expression of ERα and GPER1.