Immunolocalization of TGF-beta 2 in the rat thymus during late stages of prenatal development

The aim of this study was to investigate the immunolocalization of transforming growth factor beta (TGF-beta 2) in rat thymic stromal cells and thymocytes and investigate the roles of TGF-beta 2 in thymopoiesis during the late stages of fetal development. Twelve adult pregnant female Wistar rats weighing 250-270g were used in this study. The rats were killed by cervical dislocation on gestation days 16 (GD 16), 18 (GD18) and 20 (GD20). Fetal thymus glands were prepared and examined by an immunohistochemical technique to reveal binding of an anti-TGF-beta 2 rabbit polyclonal antibody. The thymic primordium was surrounded with a connective tissue capsule at GD16 and at this stage TGF-beta 2 immunoreactivity was not observed. At GD18, the connective tissue capsule had formed septa which subdivided the tissue into lobules and at this stage TGF-beta 2 immunolocalization was detected in the capsule and in thymocytes. Lobulation was more evident at GD20 and TGF-beta 2 immunoreactivity of thymocytes was more extensive than on GD18. Results indicate that TGF-beta 2 may play an important role in the organization or development of thymocytes in the late stages of thymopoiesis. (C) 2008 Elsevier GmbH. All rights reserved

Ultrastructural changes in the kidney of rats with acute exposure to cadmium and effects of exogenous metallothionein

Ultrastructural changes in the kidneys of rats after acute cadmium exposure and the effects of exogenous metallothionein (MT) were studied by transmission electron microscopy. Thirty-six adult Wistar rats were divided into three groups. Cadmium chloride (CdCl2) (3.5 mg/kg/day) was injected subcutaneously in the first group. In the second group, 30 mu mol/kg MT was administered in addition to CdCl2. Control rats received 0.5 ml subcutaneous saline solution. Four rats from each group were killed on days 1, 3, 5, and 7 after administration of the compounds. Kidney tissues were taken and fixed in 2.5% glutaraldehyde solution for electron microscopic observations. Tissue damage in kidney increased as time passed since the administration of CdCl2 in the first group. Degeneration in the proximal and distal tubules was observed. Increased apoptosis was seen in the proximal tubules epithelium, especially on day 7. Peritubular capillaries became dilated, there was degeneration of the endothelial cells, and the amount of intertubular collagen fibers was increased. On day 1, irregular microvilli in the proximal tubules, deepening of the basal striations, and myelin figures; on day 3, multiple vesicular mitochondria and regions of edema around tubules; on days 5 and 7, increased apoptotic cell in the proximal tubules and widened rough endoplasmic reticulum of the endothelial cells of glomerular capillaries were observed. We observed that the structural alterations that increased depending on the day of Cd administration decreased after exogenous MT administration, the dilation of the peritubular capillaries persisted, and there were degenerated proximal tubules. It was established that cadmium chloride was toxic for kidney cortex and caused structural damage. Exogenous MT partly prevents CdCl2-induced damage

Ameliorative effect of caffeic acid phenethyl ester on histopathological and biochemical changes induced by cigarette smoke in rat kidney

It was aimed to investigate the histopathological and biochemical changes in kidney tissues of rats exposed to cigarette smoke and possible protective effects of caffeic acid phenethyl ester (CAPE) on these changes. Twenty one male Wistar albino rats were divided into three equal groups. Animals in group I were used as control. Rats in group II were exposed to cigarette smoke and rats in group III were exposed to cigarette smoke and daily administration of CAPE. At the end of the 60-day experimental period, all the animals were sacrificed by decapitation. The serum samples obtained from the animals were studied for uric acid, creatinine and blood urine nitrogen (BUN) levels. Following routine histological procedures, kidney tissue specimens were examined under a light microscope. In addition, dismutase (SOD) and glutathione peroxidase (GSH-Px) enzyme activities and malondialdehyde (MDA) and nitric oxide (NO) contents were determined spectrophotometrically in tissue samples. It was found that serum uric acid and BUN levels of the rats exposed to cigarette smoke alone were elevated, although serum creatinine levels did not significantly change. Furthermore, renal SOD, GSH-Px, NO and MDA levels were significantly increased. These increases in serum BUN, and renal SOD, GSH-Px, NO and MDA levels were significantly inhibited by CAPE treatment. In light microscopic observations of tissues from rats exposed to smoke, mesangial cell proliferation in the renal corpuscles, dilatation and congestion in the peritubular capillaries and degenerative alterations in the proximal tubules were noted. There were also atrophic renal corpuscles. However, these histopathological changes were partially disappeared in the rats exposed to cigarette smoke plus CAPE. The present findings indicate that cigarette smoke causes impairment in renal structure and function, which can be prevented by CAPE administration

Effects of pinealectomy and exogenous melatonin on immunohistochemical ghrelin staining of arcuate nucleus and serum ghrelin leves in the rat

Although the main source of circulating ghrelin is the stomach, it is also present in physiologically relevant amounts in the hypothalamus. It is reported that pharmacological doses of melatonin decrease blood levels of ghrelin. Thus, melatonin (MT) may be a candidate for the regulation of ghrelin synthesis in the brain. This study was therefore undertaken to investigate possible effects of pinealectomy and exogenous melatonin on hypothalamic ghrelin amount. Serum ghrelin levels following pinealectomy and administration of melatonin were also sought. Adult male Sprague-Dawley rats were divided into four groups as sham-operated (SHAM), sham-operated with melatonin treatment (SHAM-MT), pinealectomised (PNX) and melatonin-treated PNX (PNX-MT) groups. Ghrelin staining in the hypothalamus was determined by immunohistochemistry. Hypothalamic ghrelin was not observed in PNX rats. Much higher staining was detected in SHAM-MT rats compared to SHAM group. Lack of effect of melatonin on hypothalamic ghrelin in PNX rats implicates that exogenous melatonin requires an intact pineal to exert its effects. Although there were remarkable changes in the immunohistochemical activity of ghrelin in the hypothalamic arcuate nucleus, neither pinealectomy nor exogenous melatonin significantly changed serum levels of ghrelin. We have demonstrated for the first time that the pineal gland may play a role in ghrelin amount in the hypothalamus. © 2006 Elsevier Ireland Ltd. All rights reserved

Comparative evaluation of hepatotoxic and nephrotoxic effects of aroclors 1221 and 1254 in female rats

Polychlorinated biphenyls (PCBs) are persistent environmental pollutants. This study compared effects of two PCB mixtures, Aroclors 1221 (A1221) and 1254 (A1254) on serum levels of aspartate aminotransferase (AST), alanine aminotransferase (ALT), alkaline phosphatase (ALP), urea, creatinine and uric acid in female rats. Histopathological changes in the liver and kidney were also examined. A group of adult Wistar rats served as controls. Groups II and III were subcutaneously injected with A1221 and A1254 at 10 mg/kg every other day for 6 weeks. At the end of this period, all animals were decapitated and blood samples were collected. Serum urea, creatinine, uric acid, ALT, AST and ALP levels were determined. Liver and kidney were collected for histopathological examination. They were fixed in formaldehyde and processed for light microscopy. Both A1221 and 1254 significantly elevated serum ALT (p < 0.05) and AST (p < 0.01) levels compared to the control group. Serum ALP values were significantly increased by A1221 (p < 0.05), but they were unaffected in the A1254 group. Treatment with both A1221 and A1254 significantly increased serum levels of urea (p < 0.05), creatinine (p < 0.01) and uric acid (except in the A1221 group; p < 0.005). Distinct histopathological changes including renal corpuscular atrophy, peritubular vascular congestion and dilated cortical tubules, sinusoidal dilatation, congestion and mononuclear cell infiltration were observed. These findings suggest that PCBs may cause nephrotoxicity and hepatotoxicity in female rats. Copyright © 2005 John Wiley & Sons, Ltd