The use of immunohistochemistry for evaluating the liver

Patterns of proliferation and cell differentiation during hepatic ontogeny in the alpaca

The liver has multiple functions that change throughout ontogeny. South American camelids (SAC) have unique characteristics related to adaptation to extreme environments and metabolism. However, the process of hepatic cell differentiation has not been studied in any SAC. We study the patterns of cell differentiation and proliferation in the liver of the alpaca at different times of the ontogeny, excluding the hematopoietic components. Immunohistochemical techniques were performed in 66 specimens, including embryos, fetuses, neonates and adults. Supplementary analyses were performed by lectinhistochemistry. The hepatocytic differentiation was performed by the identification of Hepatocyte (Clone: ​​OCH1ES Dako®). It began in the specimens of 1.8-2.5 cm of crown to rump length (CRL), from Days 25-29 (ovulation = Day 0), continued during gestation and intensified towards its end. The cholangiocytic differentiation was performed by the identification of cytokeratin 7 (CK7, Dako®). It was manifested at the final of gestation (specimens of 28.4 cm CRL, from Day 223 onwards). Parenchymal cells underwent a process of gradual differentiation (differentiation of hepatocytes preceded that of cholangiocytes). Cell proliferation was observed along gestation using the nuclear proliferation antigen (PCNA) and Ki-67. Hepatic organogenesis in the alpacas shares similar differentiation and proliferation mechanisms with other altricial, but phylogenetically distant, species.

Immunophenotypic analysis of the distribution of hepatic macrophages, lymphocytes and hepatic stellate cells in the adult rat liver

The liver consists of parenchymal hepatocytes and non-parenchymal cells. Non-parenchymal cells, Kupffer cells, hepatic stellate cells and cholangiocytes have crucial roles in liver homeostasis and liver pathology. To establish baseline data, this study investigated immunohistochemically the distribution of non-parenchymal cells in perivenular areas (PV), periportal areas (PP) and Glisson's sheath (GS) of adult rat liver. Liver tissues were collected from the left lateral lobe of rats. CD163-positive macrophages were seen along the sinusoid of PV and PP areas, indicating Kupffer cells. Double immunofluorescence showed, Kupffer cells partly co-expressed CD68 and MHC class II antigens in the liver. The numbers of Kupffer cells were significantly high in PP areas as compared with PV or GS areas. CD68-positive exudative macrophages were highly localized in PP and GS areas and a comparatively low PV area. MHC class II-positive dendritic cells (activated macrophages) were localized mainly in GS. Granzyme B-positive NK cells were mainly localized in the Glisson's sheath. CD3-positive T cells and CD20-positive B cells were distributed along the sinusoids of the PP and PV areas of hepatic lobules. Vimentin and glial fibrillary acidic protein (GFAP)-positive hepatic stellate cells were localized along sinusoids in the hepatic lobules of the liver. Cholangiocytes reacting to cytokeratin 19 were seen on interlobular bile ducts in Glisson's sheath of the liver. This study shows that heterogeneous macrophage populations, liver-resident lymphocytes and hepatic stellate cells localized in PP and PV areas or GS areas of the liver with cells specific patterns.

Effect of fluoride on major organs with the different time of exposure in rats

Background

High fluoride levels in drinking water in relation to the prevalence of chronic kidney disease of unknown etiology (CKDu) in Sri Lanka were investigated using rats as an experimental model.

Method

The effects of fluoride after oral administration of Sodium fluoride (NaF) at levels of 0, 0.5, 5 and 20 ppm F⁻ were evaluated in adult male Wistar rats. Thirty-six rats were randomly divided into 4 groups (n = 9), namely, control, test I, II, and III. Control group was given daily 1 ml/rat of distilled water and test groups I, II, and III were treated 1 ml/rat of NaF doses of 0.5, 5, and 20 ppm, respectively, by using a stomach tube. Three rats from the control group and each experimental group were sacrificed after 15, 30, and 60 days following treatment. Serological and histopathological investigations were carried out using blood, kidney, and liver.

Results

No significant differences were observed in body weight gain and relative organ weights of the liver and kidney in fluoride-treated groups compared to control group. After 60 days of fluoride administration, group I showed a mild portal inflammation with lytic necrosis while multiple areas of focal necrosis and various degrees of portal inflammation were observed in groups II and III. This was further confirmed by increased serum aspartate aminotransferase (AST), alanine aminotransferase (ALT), and alkaline phosphatase (ALP) activities. As compared with control and other treated groups, group III showed a significantly higher serum AST activity (p < 0.05) and ALT activity (p < 0.05) after 60 days and ALP activity with a significant difference (p < 0.05) after 15, 30, and 60 days. The renal histological analysis showed normal histological features in all groups with the elevated serum creatinine levels in group III compared to those in the groups I and II (p < 0.05) after 60 days. Significantly elevated serum fluoride levels were observed in group II of 30 and 60 days and group III after 15, 30, and 60 days with respective to control groups (p < 0.05).

Conclusion

Taken together, these findings indicate that there can be some alterations in liver enzyme activities at early stages of fluoride intoxication followed by renal damage.

Molecular pathology in the preclinical development of biopharmaceuticals

Advances in cell and molecular biology have engendered a wide range of techniques that can be used to study the molecular events that underlie the cause of disease, thus producing a new field of study called "molecular pathology." These techniques can be either slide-based or non-slide-based (solution-based). The slide-based techniques include immunohistochemistry, in situ hybridization, and in situ polymerase chain reaction; pathologists play a unique role in the administration of these techniques because of their ability to interpret the end product (i.e., the slide). In this manuscript, we briefly discussed the use and impact of these slide-based techniques within all phases of drug development in the pharmaceutical industry.