SD rats' lung function variation under various benzene concentration exposure environment.
2008
Hochschulschrift
Zugriff:
96
Benzene, a scientifically proven carcinogen, is not only common in the surroundings of industrial professionals, but it is also present in our everyday lives in minute amounts. Research has shown that long term exposure to benzene can cause harm to both humans and animals. For example, benzene administered orally for large rats has a lethal dose (LD50) of 930 mg/ Kg and an inhalation lethal dose of 9980 ppm after seven hours. Despite these research data, there is a lack of understanding on the effects of benzene on the respiratory system. So, the following experiment focuses on the effects of various benzene concentrations on the respiratory system. The methods used for this experiment involved 38 big male rats, divided into three experimental groups. Group 1 consists of six 6 months old rats weighing 450-550g, exposed to 30 ppm of benzene. Group 2 consists of sixteen 6 weeks old rats weighing 200g, exposed to benzene concentration of 300 ppm. Finally, group 3 consists of sixteen 6 weeks old rats weighing 200g, exposed to 300 ppm of benzene. The effects on respiratory function are assessed by methods of Whole Body Plethysmograph (WBP), Non-invasive Airways Mechanics(NAM), and Pulmonary Function Test (PFT). The experimental groups were exposed for 20 hrs at a time (1pm to 9am), with four hours break in between each session for respiratory assessment and document weight changes. During times of exposure, water, food, and beddings of the rats were controlled. Three phases took place. Phase 1, involved the three basic experimental groups (0 ppm, 30 ppm, and 300 ppm). Phase 2 was identical to phase 1 with an addition of a group of an open enclosure set up, in order to compare the differences between open and closed enclosure. Phase 3 tested all groups at 300 ppm, focusing on the effects of high concentration of benzene on experimental rats. Our results show, any concentration of benzene reduces the rats’ appetite, causing them to loose weight. Towards the end period of high level benzene exposure, the rats suffered from severe nose bleeds, fur boats turning red, and general feeling of their bodies. At low levels of benzene exposure, airway resistance ( Penh) shows a slight decrease. At high levels of benzene exposure, airway resistance shows a more noticeable decrease in the beginning. But towards the end, a drastic increase in airway resistance is noted. In conclusion, our results show that the initial exposure of benzene can have a relaxing effect on respiratory airways. However, chronic exposure to benzene can lead to respiratory airway destruction. Key word: Exposure system, Penh, sRaw.
Titel: |
SD rats' lung function variation under various benzene concentration exposure environment.
|
---|---|
Autor/in / Beteiligte Person: | Tsung-Ang, Cheng ; 鄭宗昂 |
Link: | |
Veröffentlichung: | 2008 |
Medientyp: | Hochschulschrift |
Sonstiges: |
|