الفهرس 
TitleOnly 14 pages are availabe for public view
 |  | from | 73 |  |  |
| | | from | 73 | | |
Abstract
Liver cancer varies widely in incidence throughout the world, with rising incidence in Egypt. Different environmental risks factors for hepatocellular carcinoma (HCC) have been identified including hepatitis B virus (HBV), hepatitits C virus (HCV), and myotoxins exposure. In addition to previously mentioned risk factors other factor such as obesity , iron overload, both alcoholic and non-alcoholic cirrhosis, as well as diatery hepatocarcinogenes such as nitrosamine , have also been implicated as important key causes of HCC.
One of the most important group of hepatocarcinogens is N-Nitroso compounds. They are found in food, also in drink water due to disinfection with cholorinated compounds. N-nitrosodimethylamine (NDMA) is the simplest aliphatic nitrosamine, which can cause cancer in a variety of organs including liver, kidney and lungs with different rout of administration. It is well established that metabolic activation of NDMA is required to exert its mutagenic and/or carcinogenic effects. However, glutathione (GSH) and its related enzyme such as glutathione-S- transeferase (GST) and γ-glutamyletranseferase (GGT) have been a key role in detoxification of NDMA.
On the other hand, the critical role of some natural products having antioxidant properties in protection against cancer, e.g., soybean, is still a matter of concern. The antioxidant properties of soybean are attributed to flavonoids which reduces the risk of chronic diseases, including coronary heart defects and cancers. Meanwhile, the role of micronutrients including vitamin C, E, carotenoids, and selenium, in defending against oxidant damage can not be ignored.
Accordingly, the present study designed to explore the protective role of co-administration of soybean-enriched diet and antioxidant vitamins against NDMA-induced hepatocarcinogensis.
The current study was conducted on the following groups of rats:
• Control (control-group): Consisted of 50 control rats.
• Soybean (Sb-group): Consisted of 50 rats fed on diet enriched with soybean for a period of 16 weeks.
• Soybean and antioxidant mixture (SAOx-group): Consisted of 50 rats received balanced diet enriched with soybean and commercial antioxidant vitamins (Antox).
• NDMA (NDMA-group): Consisted of 50 rats administered once daily by oral incubation NDMA for a period of 16 weeks.
• NDMA with soybean (NDMA-Sb group): Consisted of 50 rats fed on diet enriched with soybean and injected with NDMA as in Sb-group.
• NDMA with soybean and antioxidant mixture (NDMA-SAOx group): Consisted of 50 rats fed on diet enriched with soybean and commercial vitamins mixture (Antox) and received NDMA as in Sb- and SAOx-groups.
Blood samples were collected at the time intervals 24 hour as well as 3, 6, 12; 16 weeks post NDMA administration. The following investigations were carried out:
1- Biochemical studies
a- Determination of whole blood glutathione content (GSH) .
b- Determination of serum glutathione S-transferase activity (GST).
c- Determination of serum activity of γ-glutamyltransferase (GGT).
2- Histopathological studies
The results of the present study revealed different histopathological and biochemical changes during hepatocarcinoenesis with NDMA. These changes manifested by depletion of GSH and increased in activity levels of GST and GGT. Histopathologically, the results showed the different stages of NDMA-induced hepatocarcinogenesis. On the other hand, co-administration of soybean has only delayed the progression of NDMA-hepatocarcinogenic effects. Also, it showed an improvement in the concentration level of GSH and in activity levels of GST and GGT in 16th week post NDMA administration. This could be attributed to the antioxidant properties of soybean ingredients. Moreover, the results of the present study revealed that co-administration of soybean together with antioxidant vitamins and minerals provoked more protective role against NDMA-hepatocarcinogenesis than its administration alone. This, perhaps, could be explained on the basis of the synergism of antioxidant capacity of soybean, vitamins and minerals.
In conclusion, the data of the current study may demonstrate that exposure to NDMA resulted in different histopathological and biochemical changes. These changes manifested by depletion of GSH and increased in activity levels of GST and GGT. Histopathologically, the results may reflect the gradual progression of NDMA-induced hepatic damages. On the other hand, co-administration of soybean has delayed the progression of NDMA-damaging effects. Also, it showed an improvement in the concentration level of GSH and in activity levels of GST and GGT. This could be attributed to the antioxidant properties of soybean ingredients. However, pathologically and biochemically, the results of the present study revealed that co-administration of soybean together with antioxidant vitamins and minerals provoked more protective role against NDMA-hepatocarcinogenesis than its administration alone. This, perhaps, could be explained on the basis of the synergism of antioxidant properties of soybean, vitamins and mineral.