Rats In Exposure Group Research Articles

Effect of Sulfur Dioxide Inhalation on Lung Microbiota in Rat Model

Purpose: To investigate the effect of sulfur dioxide on the lung microbiota of healthy rats. Methods Fifteen male rats were randomly divided into high dose and low dose exposure group and control group. After 7 days of SO2 exposure, the lung tissues were obtained and the lung microbiota was identified by Illumina high-throughput sequencing. Results The microbial community of lung microbiota was significantly alternated in the exposure group and the dominant phylum changed from Firmicutes to Proteobacteria. In addition, the SO2 exposure caused the bronchial wall thickening and a large number of inflammatory cell infiltration in the lungs of rats in exposure groups. Conclusions The results suggest that SO2 can significantly alter the lung microbiota and pathological structure of the lungs.

Combined Effects of Fluoride and Cadmium on Liver and Kidney Function in Male Rats

It has been shown that cadmium and fluoride may both have adverse effects on liver and kidney functions, but most studies focus on a single agent. In this study, we observed the effects of cadmium and fluoride on liver and kidney functions using a rat model. Total of 24 Sprague-Dawley male rats were divided into four groups, one control group and three exposure groups that were given cadmium (50mg/L) and fluoride (100mg/L) alone or in combination via drinking water. At the 12th week, urine, blood, and kidney tissues were collected. Aspartate transaminase, alanine transaminase (ALT), urinary β2-microglobulin, and albumin were determined. Contents of malondialdehyde (MDA) and superoxide dismutase (SOD) in liver and kidney homogenates were measured to evaluate oxidative stress. There was a significant increase in serum ALT and urinary β2-microglobulin of rats in exposure groups compared with control. Serum ALT and urinary β2-microglobulin of rats exposed to cadmium and fluoride in combination was significantly higher than those treated with cadmium alone and fluoride alone. SOD declined significantly and MDA increased in combination group compared with control and those treated with cadmium and fluoride alone. Cadmium and fluoride co-exposure increase the liver and kidney damage compared with that exposed to cadmium or fluoride alone.

The modification of apoptosis correlated gene, protein and protein activity in rat hippocampus induced by benzo[a] pyrene sub-chronic exposure

To observe the effects of subchronic exposure to benzo[a]pyrene (B[a]P) on the mRNA and protein expression levels of apoptosis-related genes (bax, bcl-2, caspase-3, caspase-6, and caspase-9) and the activities of Caspase-3, Caspase-6, and Caspase-9 in the hippocampal neurons of rats and to investigate the neurotoxic mechanism by which B[a]P induces the apoptosis of neurons. Fifty-two healthy SD rat were randomly divided into five groups according to preliminary neurobehavioral test results: blank control group, solvent control group, and 1.0, 2.5, and 6.25 mg/kg B[a]P exposure groups; the rats in exposure groups were intraperitoneally injected with B[a]P every other day for 90 days. The Morris water maze was used to test the learning and memory ability of rats; flow cytometry was used to measure the apoptosis ratio of hippocampal neurons; real-time quantitative PCR and Western blot were used to measure the mRNA and protein expression levels of apoptosis-related genes; spectrophotometry was used to measure the activities of their en-coded proteins. Compared with the blank control group, solvent control group, and 1.0 mg/kg B[a]P exposure group, the 2.5 and 6.25 mg/kg B[a]P exposure groups hada significantly longer mean escape latency period (P < 0.05) and a significantly increased number of times of platform crossing (P < 0.05), and the 6.25 mg/kg B[a]P exposure group had significantly lower length and percentage of time spent in the platform quadrant (P < 0.05). The early apoptosis ratio rose as the dose of B[a]P increased (P trend < 0.05); the early apoptosis ratios of 1.0, 2.5, and 6.25 mg/kg B[a]P exposure groups were significantly higher than those of blank control group and solvent control group (P < 0.05). Compared with the blank control group, solvent control group, and 1.0 and 2.5 mg/kg B[a]P exposure groups, the 6.25 mg/kg B[a]P exposure group had significantly increased Bax expression (P < 0.05) and significantly decreased Bcl-2 expression and Bcl-2/Bax ratio (P < 0.05). The 2.5 and 6.25 mg/kg B[a]P exposure groups had significantly higher expression levels of Caspase-3 and Caspase-6 than the blank control group, solvent control group, and 1.0 mg/kg B[a]P exposure group (P < 0.05). The activities of Caspase-3, Caspase-6, and Caspase-9 were significantly higher in the 2.5 and 6.25 mg/kg B[a]P exposure groups than in the blank control group and solvent control group (P < 0.05). There was a positive correlation between the activities of Caspase-3, Caspase-6, and Caspase-9 and early apoptosis ratio of hippocampal neurons in rats (r = 0.793, P = 0.019; r = 0.886, P = 0.006; r = 0.773, P = 0.025). There were no significant differences in the mRNA expression of Bax, Bcl-2, Caspase-3, Caspase-6, and Caspase-9 among these groups (P > 0.05). Subchronic exposure to B[a]P can induce apoptosis of hippocampal neurons; its mechanism may be related to the fact that B[a]P can induce upregulated expression of Bax, inhibit expression of Bcl-2, lead to decrease in Bcl-2/Bax ratio, induce upregulated expression of Caspase-3 and Caspase-6, and cause increase in the activities of Caspase-3, Caspase-6, and Caspase-9.

Imaging study aboutdistribution sites of lesion areas of pulmonary fibrosis induced by paraquat

：Objective To analyze thedistribution of main lesion areas in pulmonary fibrosis induced by paraquat in rats bymeans of radiographic imaages and varied CT value by using MicroCT. Methods A total of 15male Sprague Dawley rats were randomly (random number) divided into control group andparaquat poisoned group. group. The rats in exposure group were treated with dilutesolution of paraquat (4mg/ mL) in dose of 14mg/kg injected intraperitoneally, and the ratsin control group were treated with the same volume of saline instead. The lung tissues ofall rats were scanned in vivo by using MicroCT on the 3rd, 7th , 14th and 28th days afterparaquat or saline administration, respectively. The data from scanned images, rates ofobservable signs of pulmonary fibrosis and average CT value variation in given regions(region of interest, ROI) were compared between groups and different durations afterpoisoning by using statistical methods as one factor analysis of variance (t-test).Results Compared with the control group, the rats with acute paraquat poisoning appearedvarying degrees of the signs of pulmonary fibrosis. Most of the lesion areas predominantlyspread over the lateral regions of the lower lobe of lung, and appeared mainly one weekafter paraquat poisoning. The opacity of lung shadow seen on the radiograph wassignificantly increased with time extended after exposure to PQ as a consequence of CTvalue variation in ROI, and there was no difference in the development of pulmonaryfibrosis between right lung and left lung ( P > 0. 05), but there were differences inthe extent of fibrosis at different areas in lung (P <0.05 or P < 0.01). ConclusionsThe signs of pulmonary fibrosis predominantly appeared one week after poisoning. Theopacity of lung shadow was increasing gradually during the course of pulmonary fibrosisdeveloped in rats in paraquat poisoning group, and lesion areas predominantly spread overthe lateral regions of the lower lube of lung.

The expression changes of N-methyl-D-aspartic acid receptor in hippocampus of offspring from female rats exposed to aluminum in the pregnancy and lactation

To investigate the effects of aluminum on learning and memory and the expression of N-methyl-D-aspartic acid receptor (NMDAR) of hippocampus in offspring from female rats exposed to Al in the pregnancy or lactation, and to explore the mechanism of toxic effects of Al on central nervous system (CNS) during development. The pregnant Wistar rats were randomly divided into 3 groups based on their body weight, i.e. control group was exposed to distilled water, low exposure group (0.2%AlCl3) and high exposure group (0.4%AlCl3) were exposed orally to AlCl3 in pregnancy and lactation for 6 weeks, 10 rats each group. Aluminum content in blood and brains was determined by atomic absorption spectrophotometry (AAS). Platform experiment was used to detect the abilities of learning and memory. The expression levels of NMDARs were detected by western blot assay. The Al content in blood and brains of rats in exposure groups increased significantly with Al dose, as compared with the control group (P < 0.05). In platform experiment, the incubation periods of rats in low and high exposure groups were (202.71 ± 81.99) and (19.67 ± 8.44) s respectively, which were significantly lower than that [(300.00 ± 0.00) s] in control group (P < 0.01), but the mistake times of rats in low and high exposure groups were 1.43 ± 0.85 and 2.47 ± 0.99 respectively, which were significantly higher than that (0.00 ± 0.00) in control group (P < 0.01). The Al exposure could change the proportion of NMDAR subtypes, the expression levels of NR1 and NR2B in hippocampus of newborn rats in low and high exposure groups were 25.22 ± 0.68, 81.23 ± 15.37 and 24.75 ± 0.71, 56.63 ± 7.82, respectively, which were significantly lower than those (31.69 ± 3.44, 107.61 ± 9.05) in control group (P < 0.05). Aluminum exposure in pregnancy and lactation could reduce the abilities of learning and memory in newborn rats, and change the proportion of NMDAR subtypes. The reduced NR1 and NR2B expression levels may be one of important mechanisms to influence the abilities of learning and memory in offspring.

Effect of Long Term Mobile Phone Exposure on Oxidative-Antioxidative Processes and Nitric Oxide in Rats

ABSTRACTThe effects of radiation emitted from cellular phones on humans are an emerging area of investigation. The previous studies have shown the role of oxidative stress and NO at radiofrequency exposed rats. Therefore, the purpose of this study was to investigate the effect of microwave/radiofrequency emitted from mobile phones and its possible oxidative damage. Wistar Albino rats were divided into three groups as exposure, sham and cage control. Rats in exposure group were exposed to 900 MHz microwave radiation (0.0782 mW/cm2) in a carousel for 2 hours/7 days in a week during ten months. The same process was applied to sham group but the generator was turned off. Rats in cage control group were kept in cage only during the study. The levels of catalase (CAT), myeloperoxidase (MPO), malondialdehyde (MDA), total antioxidant capacity (TAC), total oxidant status (TOS), oxidative stress index (OSI) in liver and nitric oxide (NO) levels in serum were determined to demonstrate the role of oxidative mechanisms. The increase of nitric oxide levels in exposure and sham groups were found significant compared to cage control group (p<0.01, p<0.05). Although serum NO levels increased in exposed rats, the difference between exposure and sham groups was not significant (p>0.05). MDA and TOS levels in liver tissue were found higher in exposed group compared to sham and cage control group (p<0.05). However, no significant alterations were found in other endpoints such as CAT, MPO, TAC and OSI. In this study we showed that 900 MHz radiofrequency radiation emitted from mobile phones exhibited an increase on MDA and TOS levels. Therefore, RF radiation emitted from GSM cellular phone may play a role to induce oxidative damage by increasing lipid peroxidation and oxidative stress.

Effect of Mobile Phone Exposure on Nitric Oxide Production

P-534 Abstract: The purpose of this study is to investigate the effect of Microwave/radiofrequency emitted from mobile phones on nitric oxide production in adult Swiss Albino rats. 28 rats were used in this study. The rats were divided into three groups such as exposure (n: 14), sham (n: 7) and cage control (n: 7). Rats in exposure groups were exposed to 900 MHz microwave radiation in a carousel for 2 hours/7 days in a week during ten months. Same process was applied to rats in sham group except exposure. Rats in cage control were kept in cage only during the study. At the end of the study, nitric oxide (NO) levels were measured. NO concentration was determined by UV- VIS spectrophotometer. The results of exposure group were compared with sham and cage control. However, sham and cage control rats were also compared with each other. Mann Whitney U test was used to analyze the results. Nitric oxide level of exposed and sham groups was found significant according to cage control group (p< 0.01, p< 0.05). However, enhanced NO level in exposed group was not found statistically significant (p> 0.05).