The liver is one of the most important organ in the body. It has important role in regulating various physiological processes as it is involved in most of the biochemical pathways for growth, fighting against disease, nutrient supply, energy provision and reproduction. It also plays a role in the metabolism of carbohydrate, protein and fat, detoxification, secretion of bile, storage of vitamins and removal of substances from the portal circulation and thus makes it susceptible to first and persistent attack by offending foreign compounds, culminating in liver dysfunction.
Liver is an important target of the oxidative stress because of its exposure to various prooxidant toxic compounds as well as of its metabolic function and ability to transform some xenobiotics to reactive toxic metabolites,So liver diseases have become one of the major causes of morbidity and mortality all over the world.
This study was performed by using adult albino rats, weighing between 170 and 200g . They were randomly divided into 8 groups each consisted of 6 rats as follow:
Group (I):
Group of rats were served as control group and given saline solution (0.9% NaCl) by intraperitoneal injection, twice weekly, for 6 weeks.
Group (II):
Group of rats were given 200 mg/kg body weight of thioacetamide (TAA) by intraperitoneal injection, twice weekly, for 6 weeks.
Group (III):
Group of rats were devided into three subgroups as follow :
• G-III-A:
Group of normal rats were given 6 mg/kg/d of zinc sulphate by intraperitoneal injection, for 6 weeks.
• G-III-B:
Group of normal rats were given 100 mg/kg/d of Vitamin C by intraperitoneal injection, for 6 weeks .
• G-III-C:
Group of normal rats were given 6 mg/kg/d of zinc sulphate and 100 mg/kg/d of Vitamin C by intraperitoneal injection, for 6 weeks.
Group (IV):
Group of rats were devided into three subgroups as follow :
• G-IV-A:
Group of rats were given 200 mg/kg body weight of thioacetamide(TAA) , twice weekly and 6 mg/kg/d of zinc sulphate by intraperitoneal injection, for 6 weeks.
• G-IV-B:
Group of rats were given 200 mg/kg body weight of thioacetamide(TAA) , twice weekly and100 mg/kg/d of Vitamin C by intraperitoneal injection, for 6 weeks.
• G-IV-C:
Group of rats were given 200 mg/kg body weight of thioacetamide (TAA), twice weekly, 6 mg/kg/d of zinc sulphate and 100 mg/kg/d of Vitamin C by intraperitoneal injection, for 6 weeks.
Blood samples were collected for serum preparation and biochemical estimation of liver enzymes
Liver Specimen prepared for histopathological examination with Hematoxylin and Eosin (H&E) for detection of the histopathological signs of liver cell injury and immunohistochemical examination for assisment of the degree of apoptosis as a sign of liver cell damage by using an apoptotic marker.
Results
As regard the biochemical estimation of liver biomarkers :
The results of present study showed that:
• There were high significant increases in serum liver biomarkers {Alkaline Phosphatase ( ALP), Alanine aminotransferase (ALT), Aspartate Aminotransferase (AST) and bilirubin } in addition to high significant decrease in serum albumin in group II( Group of rats were given thioacetamide ) when compared to group I (control rats) that indicate the hepatotoxic effect of thioacetamide.
• There were nonsignificant changes in serum liver biomarkers {Alkaline Phosphatase ( ALP), Alanine aminotransferase (ALT), Aspartate Aminotransferase (AST) , bilirubin and albumin } in group III-A(Group of normal rats were given zinc sulphate) when compared to group I (control rats),that indicate nonsignificant effect of zinc on normal liver biomarkers.
• There were nonsignificant changes in serum liver biomarkers in group III-B(Group of normal rats were given vitamin C) when compared to group I (control rats),that indicate nonsignificant effect of vitamin C on normal liver biomarkers.
• There were nonsignificant change in serum liver biomarkers in group III-C(Group of normal rats were given zinc sulphate and vitamin C) when compared to group I (normal control rats),that support the previous point of view as regard the nonsignificant effect of vitamin C and zinc supplementation on normal liver biomarkers.
• There were high significant decreases in serum Alanine aminotransferase (ALT) and Aspartate Aminotransferase (AST) , significant decrease in serum Alkaline Phosphatase ( ALP) and bilirubin and nonsignificant increase the level of albumin in group IV-A (Group of rats were given thioacetamide and zinc sulphate)when compared to group II (Group of rats were given thioacetamide ),which indicate the role of zinc sulphate in decreasing the hepatotoxic effect of thioacetamide.
• There were Significant decrease in the level of alanine aminotransferase(ALT/GPT), high significant decrease in the level of aspartate Aminotransferase (AST/SGOT) and nonsignificant change in the level of alkaline phosphatase(ALP),bilirubin and albumin in group IV-B (Group of rats were given thioacetamide and vitamin C)when compared to group II (Group of rats were given thioacetamide ),which indicate the role of vitamin C in decreasing the hepatotoxic effect of thioacetamide.
• *There were high significant decrease in the level of alanine aminotransferase(ALT/GPT), high significant decrease in the level of aspartate Aminotransferase (AST/SGOT) and significant decrease in the level of alkaline phosphatase(ALP) and bilirubin ,in addition to significant increase in the level of albumin in group IV-C (Group of rats were given thioacetamide,zinc sulphate and vitamin C)when compared to group II (Group of rats were given thioacetamide), which indicate the synergistic effect of zinc and vitamin C in hepatic protection against TAA induced toxicity
As regard the histopathological examination of liver:
There were multible histopathological signs indicating the hepatotoxic effect of thioacetamide,which improved in groups of rats treated with zinc and vitamin C
As regard immunuhistochemical staining: to detect the presence of BCLx (anti-apoptotic protein) in tissue sections from experimental specimens, the results showed low positive Bcl-X brown immunostaining in group II (Thioacetamide treated rats) indicating presence of small amount of Bcl-X and marked apoptosis caused by TAA. Also there were moderate positive Bcl-X brown immunostaining in group IV-A(Rats treated with thioacetamide and zinc sulphate) and group IV-B(Rats treated with thioacetamide and vitamin C) ,indicating increase in the amount of BCL-X due to decrease in the amount of apoptosis ,and there were strong positive Bcl-X brown immunostaining in group IV-C(Rats treated with thioacetamide , zinc sulphate and vitamin C) indicating the synergestic effect of zinc and vitamin C to decrease the amount of apoptosis.
RECOMMENDATIONS
• Further studies on another hepatoprotective agents.
• Further studies on the role of anti-oxidants in different types of diseases.
• Further studies on apoptosis and its role in pathophysiology of different types of disease.
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