الفهرس 
The Anatomy Of The Rat LiverOnly 14 pages are availabe for public view
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Abstract
The present study aimed at clarifying the changes that accompany different degrees of liver fibrosis and investigating the possible role of curcumin in modulating the fibrosis process and whether it could improve recovery.
Thirty adult Male Sprague-Dawley rats were utilized with an average weight of 150-200g. The animals were divided into four groups; A, B, C and D.
Group A (three animals) served as control that received no treatment.
Group B received ip injection of the vehicle only (olive oil) subdivided into two subgroups three animals each; B1 (injected for 4 weeks) and B2 (injected for 8 weeks).
Group C, induced liver fibrosis, received ip injection of 0.2ml/100g CCl4 dissolved in a 1:1 ratio with olive oil twice weekly and subdivided into three subgroups three animals each; C1(injected for 4 weeks) ,C2 (injected for 8 weeks) and C3 (injected for 4 weeks and 4weeks without CCl4 injection).
Group D, curcumin treated group, subdivided into four subgroups three animals each; D1 (received CCl4 and curcumin for 4 weeks), D2 (received CCl4 and curcumin for 8 weeks), D3 (received CCl4 and curcumin for 4 weeks followed by curcumin only for 4weeks) and D4 (received CCl4 only for 4 weeks followed by curcumin only for 4weeks).
Liver specimens obtained from each group of animals were processed to paraffin sections and stained by hematoxylin and Eosin, Masson’s trichrome stains. Moreover, immunohistochemical localization of α SMA was conducted. Image analysis of both MT and α SMA stained sectioned was performed and the collected data were statistically analyzed using the ANOVA test.
In the present work, evident changes in liver architecture were recognized following CCl4 injection for 4 weeks. These changes affected both the hepatocytes and the connective tissue stroma. The cytoplasm of pericentral hepatocytes showed different degrees of degeneration and their nuclei were darkly stained and many of them appeared flattened and eccentric in position.
Moreover, the hepatic stroma showed dense blue collagen fibers around the central vein with radiating strands encircling the degenerated hepatocytes and delineating the hepatic sinusoids. Also, bands of fibrous tissue were seen extending between the vascular elements of the hepatic lobules.
The previous group of animals showed characteristic widespread intense α-SMA reactivity in the form of brown deposits throughout the liver sections. Close examination of the distribution of this α-SMA reactivity revealed dense brown granules around the central veins, radiating in between hepatic cords and individually encircling the degenerated vacuolated hepatocytes. Moreover, dense immune reactivity ramified from the portal tract into the surrounding hepatic cords.
With prolonged administration of CCl4for another 4 weeks the liver sections, collected from the animals of group C2, presented the histological picture of liver cirrhosis. Hepatic nodules of different size and shape separated by irregular branching sheets of fibrous tissue were identified. Moreover, inflammatory cell infiltrate was seen around the congested hepatic and portal veins and through the connective tissue septa.
Image analysis of MT stained sections of this group of animals revealed a highly significant increase (p < 0.01) of the connective tissue content as compared to both control groups and group C1.
Moreover, immunohistochemical examination of liver specimens obtained from this group of animals revealed a high reactivity to α-SMA in the form of dense brown deposits. The image analysis of such α-SMA reactivity was statistically highly significant, as compared to both control groups and group C1.
In group C3, the liver seemed to regain some of its normal lobular architecture and the pericentral area showed regenerated hepatocytes with eosinophilic cytoplasm and a rounded nucleus. However, in some hepatocytes dispersed small vacuoles were identified. Moreover, binucleated hepatocytes were frequently met with in group C2 and group C3.
On the other hand, image analysis of MT stained liver sections obtained from group C3 revealed that collagen fibers content of hepatic stroma diminished significantly (p < 0.01) as compared to group C1 indicating resolution of fibrous tissue. However, the central veins were still surrounded by dense blue collagen fibers and strands of fibrous tissue were seen extending for short distances between the hepatic cords.
In correlation with the distribution of fibrous tissue seen in MT staining, the α-SMA reactivity of this group of animals showed a high significant (p < 0.01) decrease in comparison with group C1. However, brown deposits of α-SMA reactivity could be identified extending for a short distance from central veins and dispersed throughout the hepatic lobules as well.
Careful examination of liver specimens obtained from group D1 revealed evident improvement of the histological picture of the liver architecture in comparison to that of group C1. This marked improvement was manifested by the prominent decrease in the areas of degenerated hepatocytes accompanied with larger areas of normally appearing hepatocytes.
MT stained sections obtained from group D1 showed a milder form of hepatic fibrosis in comparison to that seen in group C1. In that respect thin short strands of collagen fiber were seen surrounding the central veins and extending between the degenerated hepatocytes. Moreover, fine collagen fibers were seen surrounding the portal tract elements, but extending for a short distance between the surrounding hepatic cords. These findings were confirmed by image analysis which revealed that simultaneous administration of curcumin with CCl4 significantly (p < 0.01) reduced hepatic fibrosis as compared with CCl4 only treated group.
In the present work, immunohistochemical examination of group D1 showed that curcumin administration resulted in an outstanding highly significant reduction (p < 0.01) of α-SMA reactivity within the hepatic lobules in comparison with group C1. Such reactivity took the form of fine brown deposits radiating for only a short distance from the central vein and faint reaction within the portal tract with minimal extension into the surrounding hepatic cords.
The histological examination of liver specimens obtained from group D2 showed a preserved lobular hepatic architecture with absence of any cirrhotic nodule. Moreover, masses of normal hepatocytes evidently exceeded those of degenerated ones.
Image analysis of MT stained sections of animals of the previous group showed a high significant decrease (p < 0.01) in the connective tissue content in comparison with group C2. In correlation with this decrease in connective tissue content the α-SMA reactivity for this group of animal manifested a highly significant reduction (p < 0.01) as compared to group C2.
In the present work, animals of group D3 showed marked improvement in the histological picture of the liver as compared to that of group D1. Such finding indicated that further administration of curcumin after cessation of CCl4 has a beneficial effect on the recovery of the liver. This beneficial effect was demonstrated by the high significant decrease (p < 0.01) in the content of fibrous tissue and α-SMA reactivity in comparison with D1. Moreover, there was an evident recovery of pericentral hepatocytes.
It was demonstrated that group D4 also showed an improvement in liver recovery. Moreover, immunohistochemical examination of groups D3 and D4 revealed a non significant difference (p > 0.05) in α-SMA reactivity in comparison to that of control groups. While those obtained from group C3 showed a significant increase (p < 0.05) of α-SMA reactivity in comparison to control groups.
The above mentioned histological and immunohistochemical findings were discussed in relation to the effect of curcumin on an established module of liver fibrosis.