The protective effect of hepatocyte growth-promoting factor (pHGF) against carbon tetrachloride-induced acute liver injury in rats: an ultrastructural study

Hepatoprotective activity of the neem-based constituent azadirachtin-A in carbon tetrachloride intoxicated Wistar rats

The aim of this study was to investigate the hepatoprotective role of azadirachtin-A in carbon tetrachloride (CCl4) induced hepatotoxicity in rats. The group allotment for the animals used in the hepatoprotective study included a vehicle treatment group, CCl4 (1 mL · (kg body mass)(-1)) treatment group, silymarin (100 μg · (kg body mass)(-1) · day(-1)) + CCl4 treatment group, and groups treated with different doses of azadirachtin-A (100 or 200 μg · (kg body mass)(-1) · day(-1)) + CCl4. On the 9th day, blood was obtained for measuring the biochemical parameters, and liver tissue was obtained for pathological examination. The acute toxicity test with azadirachtin-A (500, 1000, or 2000 μg · (kg body mass)(-1)) indicated no mortality after 14 days of treatment; further, there was no change in behavior, food consumption, or organ mass. However with the higher dose, some hematological parameters showed changes. Hepatoprotective studies revealed that the CCl4 treatment group exhibited a decrease in total protein and albumin levels, whereas a significant increase in BUN, AST, ALT, and ALP levels were noticed compared with the vehicle-treated control, indicating that there was liver damage caused by CCl4. Histology and ultrastructure study confirmed that pretreatment with azadirachtin-A dose-dependently reduced hepatocellular necrosis and, therefore, protected the liver against toxicity caused by CCl4. The results from this study indicate that pretreatment with azadirachtin-A at the higher dose levels, moderately restores the rat liver to normal. This study confirms that azadirachtin-A possesses greater hepatoprotective action; however, the effective concentration needs to be determined.

Ultrastructural changes in the rat kidney after single dose of cyclophosphamide—Possible roles for peroxisome proliferation and lysosomal dysfunction in cyclophosphamide-induced renal damage

Electron microscopy was used to examine changes in the subcellular organelles of the rat kidney at different time intervals after a single exposure to cyclophosphamide (CP). The morphological changes were studied at different time points (6 hrs, 16 hrs and 24 hrs) after a single-dose administration of CP. Six rats were killed at each time intervals after the administration of CP. Saline-treated rats served as controls. CP administration resulted in alterations in various subcellular organelles including peroxisomes, lysosomes, mitochondria, and the endoplasmic reticulum (ER) of the renal tubular epithelium as well as damage to the glomerulus. The basement membrane of the glomerulus was thickened. Many podocytes were destroyed. The nucleoplasm of the endothelial cell showed fewer granularities. The tubules were distorted and the brush border was destroyed. Two striking features in the renal tubular cells are increase in number and size of the peroxisomes (peroxisome proliferation) and decrease in the number of lysosomes. The mitochondria were elongated and the number was increased in the tubules of CP-treated rats. The ER was dilated. Cell necrosis was also seen. This study is an evidence of changes in morphology of rat kidney after induction of renal damage by a single dose of CP. Since transmission electron microscopy is the highest magnification tool at present, it can be useful in estimating the degree of injury and outcome of alternative treatment strategies in the management of CP-induced renal damage after establishing a scoring system.

Protective effect of apricot (Prunus armeniaca L.) on hepatic steatosis and damage induced by carbon tetrachloride in Wistar rats

The present study was planned to investigate the protective effect of 10 % and 20 % apricot-containing feed on carbon tetrachloride (CCl4)-induced hepatic steatosis and damage. Adult male Wistar rats (n 42) were divided into six groups of seven each, as follows: control group; CCl4 group; CCl4+10 % apricot group; CCl4+20 % apricot group; 10 % apricot group; 20 % apricot group. All apricot groups were fed with 10 % or 20 % apricot-containing feed for 5 months. CCl4 injections were applied to the CCl4 groups at the dose of 1 mg/kg for 3 d at the end of 5 months. In the CCl4 group, vacuolated hepatocytes and hepatic necrosis were seen, especially in the centrilobular area. Hepatocytes showed an oedematous cytoplasmic matrix, large lipid globules and degenerated organelles. The area of liver injury was found significantly decreased with apricot feeding. Malondialdehyde and total glutathione levels and catalase, superoxide dismutase and glutathione peroxidase activities were significantly changed in the CCl4 group and indicated increased oxidative stress. Apricot feeding decreased this oxidative stress and ameliorated histological damage. We concluded that apricot feeding had beneficial effects on CCl4-induced liver steatosis and damage probably due to its antioxidant nutrient (beta-carotene and vitamin) contents and high radical-scavenging capacity. Dietary intake of apricot can reduce the risk of liver steatosis and damage caused by free radicals.

Ultrastructural changes in hepatocytes after taurine treatment in CCl4 induced liver injury

AIM: To search the organelle based changes in hepatocytes after taurine treatment in experimental liver fibrosis induced by CCl₄ administration.

METHODS: Thirty rats were divided into two groups. Group 1 (n = 15) was injected with CCl₄ plus taurine and Group 2 (n = 15) with CCl₄ plus saline for 12 wk. At the end of 12th wk, mitochondria, rough and smooth endoplasmic reticulum, and nuclei of hepatocytes were evaluated using a scoring system. The results were compared with histopathological findings, as well.

RESULTS: Taurine treatment reduced fibrosis scores significantly as compared to placebo. Organelle injury scores decreased significantly with taurine treatment. Ultrastructural and histopathological scores in both groups were in strong correlation (r = 0.931 for CCl₄ plus taurine and r = 0.899 for CCl₄ plus saline group).

CONCLUSION: Organelle based transmission electron microscopy findings can reflect successfully histological results as well as tissue healing in hepatocytes from hepatotoxin-induced liver fibrosis.

Molecular process in acute liver injury and regeneration induced by carbon tetrachloride

Injection of carbon tetrachloride (CCl4) intraperitoneally into model animals induces acute liver injury mediated by reactive oxygen species (ROS) as normal metabolites in hepatocytes. In this study, the molecular process in this type of liver injury was analyzed from the aspect of liver function and regulatory factors. Down-regulation of liver-specific genes was accomplished through suppression of liver-enriched transcription factors and box A factors found in the catalase gene, and induction of NF-kappaB, AP-1 and a novel factor denoted as 'cx' in the catalase gene. Expression profiles of these genes were restored to normal levels in the late stage of injury (48 h). On the other hand, hepatocyte growth factor (HGF) and proliferating cell nuclear antigen (PCNA) were induced in the early stage (6 h) and 36 h, respectively. Interestingly, ERK2 was transiently activated at 3 h CCl4-treatment. These observations suggested that hepatotoxin by CCl4-injection concomitantly induces both processes in acute injury and liver regeneration.

[The protective effect of hepatocyte growth-promoting factor (pHGF) against carbon tetrachloride-induced acute liver injury in rats. II. Protective effects on cell membrane injury]

To examine the protective effects of hepatocyte growth-promoting factor (pHGF) against carbon tetrachloride (CCl4) -induced acute liver injury in rats, the pathological changes were observed by light and electron microcopy, and the serum GOT and GPT levels were measured. Acute liver injury was produced by the injection of CCl4 (2ml/kg BW) in two groups of animals, of which one received pHGF (300 microg/kg BW) via the tail vein after 4 hrs. In the group treated with CCl4 alone, serum GOT and GPT were significantly elevated (1280+/-228 and 187+/-73 IU/l, respectively) 6 hrs after injection, indicating the induction of liver injury by CCl4. They reached a peak (3836+/-654 and 1022+/-230 IU/l, respectively) at 48 hrs and declined thereafter, but did not completely recover after 72 hrs. PAS-negative cells were observed around the central veins after 6 hrs and most of the hepatocytes were PAS-negative at 12 hrs. PAS-positive cells began to appear and increased in number after 24 hrs. There were scarcely any PAS-negative cells remaining in the lobules after 72 hrs. In the group treated with CCl4 followed by pHGF, serum GOT and GPT levels were significantly lower than in the CCl4-treated group, and abundant PAS-positive hepatocytes were observed. Also, all hepatocytes were PAS-positive (as in normal liver) after 72 hrs. Administration of pHGF resulted in a decrease in the ultrastructural changes in rats with CCl4-induced liver injury such as vacuolation, cisternae formation and dilatation of the rough endoplasmic reticulum. These results suggest that pHGF acts to stabilize cell membranes, thereby providing protection against CCl4-induced hepatic injury.