[DNA damage of splenic lymphocytes in pregnant mice exposed to carbon disulfide in implantation phase].

OBJECTIVE: To investigate the DNA damage of splenic lymphocytes in pregnant mice exposed to carbon disulfide (CS2) in the implantation phase and to explore the mechanism of abnormal implantation induced by CS2 from the perspective of immune injury. METHODS: Mice were exposed to CS2 at different doses or at different time points in the implantation phase to establish model 1 and model 2. For model 1, mice were assigned to four groups to receive a single intraperitoneal injection of low-dose CS2 (0.1 LD50, 157.8 mg/kg), middle-dose CS2 (0.2 LD50, 315.7 mg/kg), and high-dose CS2 (0.4 LD50, 631.4 mg/kg) as well as an equal volume of olive oil (control) on gestational day (GD) 4. For model 2, mice were assigned to four groups to receive a single intraperitoneal injection of CS2 (0.4 LD50, 631.4 mg/kg) or an equal volume of olive oil (control) on GD3, GD4, GD5, and GD6. At the end, single cell suspension of splenic lymphocytes was prepared. Cell viability was measured by trypan blue staining, and the DNA damage of splenic lymphocytes was evaluated by alkaline single cell gel electrophoresis assay. RESULTS: The middle-dose and high-dose exposure groups showed significantly more DNA damage of splenic lymphocytes than the control group (P < 0.01); there was significant regression relationship between indicators of DNA damage and exposure doses (P < 0.01). The GD3, GD4, GD5, and GD 6 exposure groups showed significantly more DNA damage of splenic lymphocytes than the control group (P < 0.01), and the GD 4 exposure group had the most DNA damage. CONCLUSION: Exposure to CS2 in the implantation phase can induce DNA damage of splenic lymphocytes in pregnant mice, and the DNA damage was aggravated with the increase in CS2 concentration. GD4 may be the sensitive time point for DNA damage of splenic lymphocytes induced by CS2 in pregnant mice.

[Effects of carbon disulfide exposure during peri-implantation on estrogen receptor-α expression in uterus and serum level of estrogen in pregnant mice].

OBJECTIVE: To evaluate the effects of carbon disulfide (CS(2)) exposure during peri-implantation on the estrogen receptor-α (ER-α) expression in the uterus and serum level of estradiol (E(2)) in pregnant mice, and to explore the mechanism of embryotoxicity of CS(2). METHODS: Healthy female mice were exposed to a single dose of CS(2) (631.4 mg/kg) or olive oil (solvent control) on gestational day (GD)3, GD4, GD5, or GD6. At different time points after exposure, the serum E(2) levels of the pregnant mice were measured by enzyme-linked immunosorbent assay, and the expression levels of ER-α in the uterus were measured by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and Western blot. RESULTS: Compared with the control group, the GD3, GD4, GD5, and GD6 exposure groups showed significantly decreased serum E(2) levels on day 7 of gestation (P < 0.05); the GD3 and GD5 exposure groups showed significantly decreased serum E(2) levels on day 6 of gestation (P < 0.05). The expression level of ER-α in the GD 4 exposure group was 23.6% lower than that in the control group on day 5 of gestation, and the expression level of ER-α in the GD 5 exposure group was 72.9% lower than that in the control group on day 6 of gestation (P < 0.05); the GD 3 and GD 6 exposure groups showed lower expression levels of ER-α than the control group at any time point, but no significant difference was found (P > 0.05). CONCLUSION: CS(2) exposure during peri-implantation can reduce the ER-α expression in the uterus and the serum level of E(2) in pregnant mice, which may be one of the mechanisms of embryotoxicity of CS(2).

Breastfeeding and maternal hypertension and diabetes: a population-based cross-sectional study.

OBJECTIVE: This study aimed to assess the association of breastfeeding and maternal hypertension and diabetes in Beijing, China. SUBJECTS AND METHODS: A cross-sectional study was conducted in four urban communities of Beijing, China, with 9,128 parous women 40-81 years of age who had had only one lifetime birth. Each participant completed a detailed survey and accepted blood pressure measurement and blood glucose testing. Moreover, self-reported hypertension and diabetes were confirmed by review of medical records. RESULTS: After the analysis was adjusted for the potential confounders, including age, body mass index (BMI), waist to hip ratio (WHR), working status, educational level, drinking, smoking, family history of hypertension, age of menarche, menopause, oral contraceptive use, age of child-bearing, and postpartum BMI, the odd ratio (OR) of hypertension was 1.18 (95% confidence interval [CI], 1.05-1.32) for women who did not breastfeed, compared with women who did. In addition, the ORs for >0 to 6 months, >6 to 12 months, and >12 months of breastfeeding were 0.87 (95% CI, 0.76-0.99), 0.83 (95% CI, 0.68-1.00), and 0.79 (95% CI, 0.65-0.97), respectively, compared with women who did not breastfeed. With adjustment for age, WHR, working status, educational level, family history of diabetes, and postpartum BMI, women who did not breastfeed increased the risk of diabetes (OR=1.30; 95% CI, 1.11-1.53) compared with women who did. Moreover, women who breastfed for >0 to 6 months (OR=0.81; 95% CI, 0.67-0.98) and >6 to 12 months (OR=0.46; 95% CI, 0.26-0.84) had a lower risk of diabetes, compared with women who did not breastfeed. CONCLUSIONS: Chinese mothers who did not breastfeed were more likely to develop hypertension and diabetes in later life.