Pancreatic stellate cells and alcohol induced chronic pancreatitis in albino rats: histological and immunohistochemical study

Pancreatic stellate cells [PaSCs] are myofibroblast-like cells found in the areas of pancreas that have exocrine function. The aim of the present work was to study the pancreatic stellate cells in the exocrine pancreas and to explain their role in pancreatic fibrosis associated with chronic alcoholic pancreatitis. Forty adult male rats were used in this study. The animals were divided into two groups; control and experimental. The experimental group was given alcohol by intragastric tube daily for 8 weeks. At the end of the experiment the animals were sacrificed and the pancreatic tissue was taken, processed and semithin and paraffin sections were obtained. Paraffin sections were stained with H and E, Mallory trichrome and immunohistochemical stains for detection of alpha smooth muscle actin [alpha-SMA] in PaSCs. Eight weeks after alcohol administration, the pancreatic tissue was traversed by thick connective tissue septa. The interlobular ducts were thickened, distorted and dilated. Some pancreatic acini were distorted, dilated and showed vacuolation and degeneration of their acinar cells. PaSCs were detected in three main sites like in control pancreas; periacinar, periductal and perivascular, but they showed an apparent increase in their number, decrease in their lipid droplets and transformtion into myofibroblast like cells with marked expression of alpha-SMA especially in the fibrotic areas. From the present work it was concluded that the cells which were detected seem to be the pancreatic stellate cells which could play an important role in the development of pancreatic fibrosis associated with alcoholic chronic pancreatitis. Therefore, understanding the biology of PaSCs may offers potential therapeutic targets for the treatment and prevention of these diseases

Apoptosis and phagocytosis of allogenic blood elements in the spleen of rabbit after intravenous infusion

After the recent introduction of blood cell separators, separate blood cell components became available for therapy of the serious hematologic diseases. However, unmatched transfused leukocytes and platelets express a variety of antigens that can be recognized by immunoglobulins of the recipients. Since these transfusion trials were clinically disputed, an experiment was designed to study the ultra structural changes of these cells during apoptosis and phagocytosis processes in the spleen of adult rabbit over 24 hours period after intravenous infusion of allogenic formed blood elements. Blood formed elements were found to be trapped early inside the splenic parenchyma in samples taken two hours after infusion. Apoptosis occurred earlier in polymorph nuclear leukocytes probably due to their high content of hydrolytic enzymes. Splenic macrophages were easily identified among the heavy cellular population composing the splenic parenchyma by their general morphology and containment of lysosomes and digestive vacuoles. The phagocytic activity of these cells was found to be directed toward transfused allogenic dying and even apparently normal formed blood elements. Based on the previous data, it may be concluded that the transfused allogenic blood formed elements readily become trapped and phagocytosed early in the splenic filter. This in vivo model may provide us a simple method to the histopathological structural characteristics associated with the clinically described refractory responses to transfusion therapy and evokes inquiry about the value of unmatched leukocytes and platelets transfusions

Age related ultrastructural changes in albino rat sciatic nerve and the effect of antioxidants

The present study was performed to clarify the age related ultrastuctural changes of the myelinated fibres in the sciatic nerve of albino rats and to elucidate the effects of receiving antioxidants on such age alterations. Thirty male albino rats were used in this investigation; 10 were adult [3- month- Old], ten were aged [24- month -old] and the last ten were aged but received vitamins C and E for 4 weeks. Then, all rats were decapitated and their sciatic nerves were rapidly dissected and toluidine blue- stained semithin sections were prepared for light microscopic examination. Ultrathin sections were processed for transmission electron microscope examination. Compared to the adults, the sciatic nerves of the aged rats possessed thinner perineurium. The endoneurium was collagen filled and contained many fibrocytes. The myelin sheath showed thickening, invagination, evagination, heterogeneity, splitting and myelin bubbles. The cytoplasm of Schwann cells housed rough endoplasmic reticulum, mitochondria and many electron dense bodies. The axoplasm was compressed in some areas and occasionally housed membrane bound vesicles containing heterogenous granular material and low electron dense vacuoles containing myelin figures. The unmyelinated axons were present in groups burned in deep recesses on the surface of Schwann cells. The sciatic nerves of rats received vitamins C and E showed minute splitting, infolding and outfolding of the myelin sheath. In some situations, fibrocytes extended their processes and encircled the nerve fibres, despite the improvement of the condition of the myelin. The axoplasm exhibited sequestration of the degenerated parts that contained membrane bound vesicles of low electron density. Based on the previous data, it may be concluded that, age affected the myelinated fibres of the sciatic nerve and the intake of vitamins C and E lessened such influences

Development of granulocytes and monocytes in adult rabbit bone marrow ultrastructural aspects

The hematopoietic tissue of bone marrow constitutes a heterogeneous family of indistinguishable pleuripotential stem cells; they subsequently pass through a series of developmental stages that are microscopically identifiable. The aim of the present work was to throw mor light on the development of blood granulocytes in the red bone marrow of adult rabbit using the electron microscope.in bone marrow, developing granulocytopoietic series appeared to be grouped into clusters. Among these cells, myeloblasts were characterized by a relatively large nucleus with fully granular chromatin. The cytoplasm contained much free eibosomes. During the prom yelocyte stage, Iry granules being to be formed, while the maturation sequence was evidenced by change in the nuclear configuration and size and by the appearance 2ry granules which later on dominated over the Iry type. In this study it was observed that the myelocytes nuclei were rounded or oval in shape. However, gradual elongation and indentation of the nucleus was the initial sign of maturation from myelocyte to metamyelocyte. After that, nucear remodeling continued forming the staff granulocyte, and later on constrictions appeared to segment the nucleus into two or more lobes and thus a muture segmented granulocyte was formed. A characteristic feature in eosinophilic granulocytes was their 2ry specific granules which contained electron dense crystals. Monoblasts had similarities with their mature forms, but the chromatin was homogeneously fine and granular and the cytoplasm was entirely devoid of granules, while promonocytes contained small clear vesicles. The maturation of the latter cell into monocyte was associated with development of lysosomal granules and an increase of condensed chromatin with a progressive decrease in the number of ribosomes