Induction of Endoplasmic Reticulum Stress by Cadmium and Its Regulation on Nrf2 Signaling Pathway in Kidneys of Rats.

OBJECTIVE: This study was conducted to investigate the regulation of endoplasmic reticulum stress on Nrf2 signaling pathway in the kidneys of rats. METHODS: Rats were divided into twelve groups of six animals each. Some groups were pre-administered with bacitracin or tauroursodeoxycholic acid (TUDCA), and all of them were treated with 5-20 µmol/kg cadmium (Cd) for 48 h. The oxidative stress levels were analyzed using kits. The mRNA and protein expression levels of endoplasmic reticulum stress-related factors and Nrf2 signaling pathway-related factors were determined using RT-PCR and western blot. RESULTS: Cd exposure resulted in oxidative stress in the kidneys of rats and upregulated the expression of endoplasmic reticulum stress (ERS)-related factors and Nrf2 signaling pathway-related factors, especially at doses of 10 and 20 µmol/kg Cd, and the expression changes were particularly obvious. Moreover, after pretreatment with bacitracin, Cd upregulated the expression of ERS-related factors to a certain extent and, at higher doses, increased the mRNA expression of Nrf2. After pretreatment with TUDCA, Cd reduced the level of ERS to a certain extent; however, at these doses, there were no significant changes in the expression of Nrf2. CONCLUSION: Cadmium can result in ERS and oxidative stress in the kidneys of rats, activate Nrf2, and upregulate the transcriptional expression of phase II detoxification enzymes under these experimental conditions. ERS has a positive regulation effect on Nrf2 signaling pathway but has little effect on the negative regulation of Nrf2 signaling pathway in cadmium toxicity.

[A follow-up study on dietary factors of kidney stones in Bao'an district, Shenzhen City].

OBJECTIVE: To evaluate the major dietary factors of kidney stones in Bao'an District of Shenzhen City and provide a scientific base for further effective prevention of kidney stones. METHODS: Following the process of stratified cluster random sampling in Bao'an district, a cross-sectional study (July-Aug, 2000) was conducted for collecting the base-line data on kidney stones from a population of permanent residents who were over 15 years old, exclusive of those who had had kidney stones or could not correctly respond to the questionnaire review. Then, a follow-up survey (July-Sept, 2002) for incident kidney stone cases was carried out among those residents. The methods for measurement included questionnaire and face-to-face interview, clinical examination and abdominal ultrasonography. All the investigators and interviewers were trained for the field work. And the data processing, dataset and analyses were performed using Visual-Fox 6.0 and SAS 6.12. The risk factors of kidney stoned were comprehensively analyzed for dietary, life style, and family history of stones. The statistical analyses included case-control comparison, factor analysis, correlation analysis, cluster analysis and logistic regression. RESULTS: There were 305 kidney stones patients among 4552 follow-up members, the cumulative incidence of 2 years was 6.92%. The kidney stones were associated with the factors: menopause, RR=2.433; family history of stones, RR=1.544; sea foods, the RR (5-7 times/week vs < or = 1-2 times/month) was 9.032; fruits, the RR (< or = 1-2 times/month vs > or = 1-2 times/week) was 2. 249; sweet foods, the RR (5-7 times/week vs 1-2 times/week) was 2. 568; bean and bean products, the RR (5-7 times/week and < or = 1-2 times/month vs 1-2 times/week) was 2.184 and 1.689. CONCLUSION: Changing the inappropriate habitual eating patterns and generalizing the use of proportioning dietary should be the main measures to prevent kidney stones.