Effects of typical phthalate esters on lipid metabolism in rats and its potential mechanism / 环境与职业医学

Background Di(2-ethylhexyl)phthalate (DEHP) and dibutyl phthalate (DBP) are representative environmental endocrine disruptors of phthalate esters (PAEs). Some studies have shown that PAEs exposure may have an impact on lipid metabolism. Objective To investigate the effects of DEHP and/or DBP on lipid metabolism in rats and their possible mechanisms of action. Methods Thirty-six weaned healthy SD male rats, 3 weeks old, weighing 50-70 g, were divided into four groups, i.e., a corn oil control group, a DEHP (750 mg·kg−1) group, a DBP (500 mg·kg−1) group, and a DEHP+DBP (750 mg·kg−1+500 mg·kg−1) group. The rats were exposed to DEHP and/or DBP by oral gavage for 8 weeks, and weighed once a week. The rats were anesthetized 24 h after the last dose, and blood was taken from the apical part of the heart. Serum high density lipoprotein-cholesterol (HDL-C), low density lipoprotein-cholesterol (LDL-C), total cholesterol (TC), and triglyceride (TG) were detected. Liver tissues and perigenital adipose tissues were collected, weighed, and one portion of the tissues was fixed in 10% neutral formalin for pathomorphological observation, and another portion was used for mRNA detection of lipid metabolism-related genes such as Janus kinase 3 (JAK3), signal transducer and activator of transcription 5b (STAT5b), and peroxisome proliferator-activated receptor γ (PPARγ). Results During the DEHP and/or DBP exposure period, the rats in all groups were free to eat and drink without death or injury observed. Compared with the control group: The body weight gain in the DEHP+DBP group was lower at all time points from the 2nd week onwards (P<0.05); the liver organ coefficients of the DEHP and the DEHP+DBP groups were higher (P<0.05); the serum LDL-C levels in the DEHP and the DBP groups were higher (P<0.05). Compared with the DEHP+DBP group: The body weight gains in the DEHP group at the 2nd, 4th, 5th, and 8th weeks were higher (P<0.05), and the body weight gains in the DBP group were higher at all time points except the 1st week (P<0.05); the liver organ coefficients in the DEHP group and the DBP group were lower (P<0.05); the serum TG level in the DEHP group was higher(P<0.05), and the serum LDL-C levels in the DEHP and the DBP groups were higher (P<0.05). The pathomorphological results of liver tissues showed that the hepatocytes in the DEHP, DBP, and DEHP+DBP groups were disordered with loss of cord-like arrangement, swelling (suggesting change of cell proliferation), and presented bilirubin pigmentation. The pathomorphological results of rat perigenital adipose tissues showed had irregular alignment, sizes, and arrangement of adipocyte in the DEHP, DBP, and DEHP+DBP groups. The results of rat liver lipid metabolism-related gene mRNA levels showed that the liver JAK3, STAT5b, and PPARγ mRNA levels in the DEHP, DBP, and DEHP+DBP groups were lower than those in the control group (P<0.05); the rat liver PPARγ mRNA levels in the DEHP and DBP groups were lower than those in the DEHP+DBP group (P<0.05). Conclusion DEHP and/or DBP can inhibit the increase of body weight to varying degrees, induce inflammatory damage to liver tissues, and cause abnormal lipid metabolism in rats, and the associated mechanism may be related to inhibiting the activation of JAK3/STAT5b/PPARγ signaling pathway in rat liver tissues.

Inhibition of the TGF-β/Smad3 signaling pathway by SB431542: A study of the intervention effect of SB431542 on silicotic fibrosis in rats / 中华劳动卫生职业病杂志

Objective@#To investigate the intervention effect of SB431542, which inhibits the TGF-β/Smad3 signaling pathway, on silicotic fibrosis in rats.@*Methods@#A total of 40 specific pathogen-free Sprague-Dawley rats were divided into normal saline control group, model group, SB431542 inhibitor group, and SB431542 inhibitor control group using a random number table, with 10 rats in each group. All rats except those in the normal saline control group were given non-exposed single intratracheal instillation of free silicon dioxide dust suspension 1 mL (50 mg/mL) ; the rats in the SB431542 inhibitor group were given intraperitoneal injection of SB431542 (5 mg/kg) on days 7 and 30 after dust exposure, those in the SB431542 inhibitor control group were given intraperitoneal injection of SB431542 cosolvent (5 mg/kg) on days 7 and 30 after dust exposure, and those in the normal saline control group were given intratracheal instillation of an equal volume of normal saline (5 mg/kg). On day 60 after dust exposure, the paraffin-embedded section of the right upper lobe of lung was collected for HE staining; the left upper lobe of lung was collected to measure the mRNA levels of fibronectin (FN) , collagen type I (COL-I) , and collagen type III (COL-III) by quantitative real-time PCR; the right inferior lobe of lung was collected to measure the protein levels of FN, COL-I, COL-III, phosphorylated Smad3 (p-Smad3) , and Smad3.@*Results@#Compared with the normal saline control group, the model group had nodules with various sizes in lung tissue, with rupture of some alveolar septa, emphysema changes, and pulmonary interstitial fibrosis, as well as significant increases in the mRNA expression of FN, COL-I, and COL-III and the protein expression of FN, COL-I, COL-III, p-Smad3, and Smad3 in lung tissue (P<0.05) . Compared with the SB431542 inhibitor control group, the SB431542 inhibitor group had a relatively complete structure of lung tissue without marked nodules and with a small amount of exudate in alveolar space and the lumen of bronchioles, as well as significant reductions in the mRNA expression of FN, COL-I, and COL-III and the protein expression of FN, COL-I, COL-III, p-Smad3, and Smad3 in lung tissue (P<0.05) . There were no significant differences in the mRNA expression of FN, COL-I, and COL-III and the protein expression of FN, COL-I, COL-III, p-Smad3, and Smad3 between the model group and the SB431542 inhibitor control group (P>0.05) .@*Conclusion@#SB431542 exerts an intervention effect on silicotic fibrosis by blocking the TGF-β/Smad3 signaling pathway and reducing the expression of the downstream fibrosis factors FN, COL-I, and COL-III.

Association between occupational psychological stress and metabolic syndrome / 中华劳动卫生职业病杂志

<p><b>OBJECTIVE</b>To investigate the association between occupational psychological stress and metabolic syndrome (MS) in Hui and Han populations in Ningxia, China.</p><p><b>METHODS</b>A 1:1 matched case-control study was performed. A total of 600 unrelated patients aged from 20 to 60 years who were clearly diagnosed with MS in General Hospital of Ningxia Medical University and Wuzhong People's Hospital from October 2011 to October 2012 were collected as the case group (MS group). A total of 600 healthy people who underwent a regular health examination in the same hospital during the same period were selected as the control group with matched gender, nationality, and age (≤ ± 3 years). The self-designed questionnaire was used to investigate the general situations and do the physical examination, and the fasting venous blood samples were collected for laboratory biochemical blood tests. The Occupational Stress Inventory (OSI) was used to investigate the subjects' occupational stress factors and stress levels.</p><p><b>RESULTS</b>With the increase in stress levels, the levels of WC, FPG, TG, AST, and UA were increased, WHR, SBP, and DBP first increased and then decreased, and the level of HDL-C increased. There were statistically significant differences in these parameters between the two groups (P < 0.05 or 0.01). The occupational psychological stress test results showed that the total score of stress factors (t = 6.676, P < 0.05), workload (t = 10.269, P < 0.05), interpersonal relationship (t = 6.569, P < 0.05), family/work balance (t = 2.028, P < 0.05), cognitive load (t = 8.714, P < 0.05), and other scores (t = 2.838, P < 0.05) in the MS group were all significantly higher than those in the control group, but there were no significant differences in the scores of management role, work responsibilities, and organizational climate between the MS group and the control group (P>0.05). There were no significant differences in the total score of stress factors and the score of each factor between Hui and Han groups (P>0.05). The relative risks of MS in the people with moderate stress exposure were 2.325 and 2.331 times those in the people with mild stress exposure before and after adjustment for age, gender, education level, marriage status, smoking, and drinking, and the relative risks for MS in the people with severe stress exposure were 3.000 and 3.126 times those in the people with mild stress exposure. There were significant differences in the detection rates of abdominal obesity, high TG, low HDL-C, hypertension, hyperglycemia, and diabetes between the sub-groups with different stress levels in the MS group (χ² = 17.636, 8.514, 14.640, 14.280, and 33.323, P < 0.01). The results of multivariate conditional logistic regression analysis showed that the risk factors for MS were SBP, TG, LDL-C, UA, BMI, fasting blood glucose, family history of hypertension, family history of diabetes, and the level of psychological stress in Ningxia, and the protective factor for MS was HDL-C.</p><p><b>CONCLUSION</b>The occupational psychological stress is closely associated with MS, and it is an environmental risk factor for MS. With the increase in the stress level, the detection rates of MS components and the relative risk for MS are significantly increased. And there is no significant difference in the level of occupational psychological stress between the Hui and Han nationality groups.</p>

Association of TNF-αand HSP70 in serum with type 2 diabetes mellitus among Hui and Han nationalities in Ningxia / 军事医学

Objective To investigate the expression level of tumor necrosis factor α( TNF-α) , heat shock protein 70 (HSP70) in serum and to analyze the correlation of TNF-αand HSP70 with the incidence of type 2 diabetes mellitus (T2DM) among Hui and Han nationalities in Ningxia .Methods Using the method of case-control study and according to the inclusion and exclusion criteria of case and control groups , 225 patients with T2DM who were treated by Department of Endocrinology and 600 healthy people during health checkups were enrolled in the study between October 2011 and October 2012 .A double antibody sandwich enzyme-linked immunosorbent assay ( ELISA) was used to determine the protein expres-sion levels of TNF-αand HSP70 in serum.Results The expression levels of TNF-αin the total population investigated and Hui population in T2DM group were significantly higher than in the control (t=-3.512,-3.791,all P0.05).The elevated serum levels of TNF-αincreased the risk for T2DM(OR=1.500, 95%CI:1.075-2.093,P=0.017).The expression levels of TNF-αin the total people, case and control of Hui people were significant lower than the homologous Han people (t=9.373,2.223,9.734, all P<0.01 or 0.05).Pearson analysis showed that the high expression of TNF-αwas positively correlated with blood glucose level (r=0.110,P=0.001),but there was no correlation between the high expression of HSP 70 and blood glucose level (r=0.023, P=0.504).The result of multiple logistic regression analysis indicated that gender and waist-to-hip ratio(WHR) were risk factors for high levels of TNF-α(P<0.01 or 0.05)while HSP70 and nationalities were protective factors.Systolic blood pressure(SBP) and WHR were risk factors for the high level of HSP70(all P<0.01), but TNF-αwas protective factors.HSP70, TNF-α, gender, family history, BMI, SBP, triglycerides(TG), low density lipoprotein cholesterol (LDL-C), alanine trans-aminase(ALT), and psychological stress were risk factors for T2DM, but high density lipoprotein cholesterol (HDL-C) was a protective fac-tor.Conclusion The high expression of TNF-αin serum is closely related to elevated fasting plasma glucose ( FPG) and T2DM onset.The expression level of TNF-αin serum in Hui people is lower than in Han people ,possibly correlated with ethnic heredity.The high expression of HSP70 in serum may induce T2DM onset.

Study on plantaer pressure distribution of people walking with different backpack load / 生物医学工程学杂志

The purpose of this study was to investigate the effect of different backpack load on the plantar pressure of people during walking. By using three-dimensional force platform system, we collected the ground reaction force data from 20 college students, who were carrying different loads on their backs, and then we transformed the data into a characteristic two-peak curve. Seven characteristic parameters on the curve were selected and analyzed by using statistical methods. The results indicated that the peak ground reaction forces increased as the loads increased. Furthermore, in consideration of different genders, the amount increased was different. For the male subjects, when backpack load reached 17% body weight, changes in ground reaction force began to take place until the backloads reached 20% body weight changes in ground reaction force induced a significant difference. Por the female subjects, changes in ground reaction force began to take place with loads up to 14% body weight and while it reached 15% body weight it induced a significant difference.

Surface Electromyography of Lower Limbs during Activities of Daily Living for Normal Adults / 中国康复理论与实践

@# Objective To survey the characteristics of surface electromyography (sEMG) of lower extremity during the activities of daily living (ADL). Methods 30 normal adults performed 7 basic activities, while their average electromyography (AEMG) of sEMG of rectus femoris, vastus medialis, vastus lateralis, gastrocnemius, anterior tibialis, and soleus was determined. Results and Conclusion The AEMG of lower limbs during the ADL was different in left or right, male or female, and different muscles.