Immunohistochemical expression of vascular endothelial growth factor receptors FIt1 and KDR in the endometrium during the estrus cycle in albino rats

Angiogenesis is an important process in endometrial development and embryonic implantation and is regulated through vascular endothelial growth factor [VEGF]; its receptors Flt1 and KDR. This work aimed to study the immunoexpression of VEGF receptors [VEGF-Rs] in the endometrium at different ages and reproductive phases and correlate them with the histological profiles in these phases. Seventy female albino rats were included in this study. They were divided into seven groups of 10 rats each: one group consisted of rats in the prepubertal period at age 4-6 weeks; five groups consisted of rats in the reproductive period at age 6-10 months, which were divided according to estrus cycle phases into proestrus, estrus, metestrus, diestrus, and pregnant groups; and the sixth group consisted of rats in the postmenopausal period at age 15-18 months. The uteri of all rats were removed and processed for staining with H and E and were subjected to immunohistochemical staining for Flt1 and KDR. For morphometric measurements, uterine wall thickness and Flt1 and KDR optical density in the endometrial surface epithelium, glandular epithelium, stromal cells, and endometrial endothelial cells were measured using image analysis. Results were statistically compared. The expression of VEGF-Rs was highest in the pubertal age group with marked expression of these receptors in the proestrus phase followed by the estrus phase. This supports the role of sex hormones, especially the estrogen hormone, in regulating VEGF-R expression. The Flt1 receptor was predominantly expressed in endometrial and stromal cells as well as in blastocysts, whereas the KDR receptor was predominantly expressed in endometrial endothelial cells. Comparison among all groups and then between each two groups revealed statistically significant differences in the measured morphometric parameters. The upregulation of Flt1 and KDR could be involved in the regulation of endometrial endothelial cell proliferation and in increase in endometrial vascular permeability, especially at implantation sites

Spheroid and monolayer cultures of male albino rat hepatocytes: a comparative study of in-vitro and ultrastructural features

This study was designed to compare the morphology and function of rat hepatocytes cultured as spheroids and as conventional monolayers for Ten days. Hepatocytes were isolated from liver of 15 male albino rats [8-10 weeks old] and cultured on the basal William's E medium. For spheroidal cultures, the tissue culture plates were coated with 2.5% pHEMA, whereas, for the conventional mnonolayers, the tissue culture plates were coated with rat tail collagen. Hepatocyte integrity and morphology were assessed by inverted phase-contrast and electron microscopies. Hepatocyte function was measured by the albumin secretion of the cells in the culture medium. The study revealed that hepatocytes cultured as spheroids retained a more in vivo-like morphology including their polyhedral/round shape together with normal ultrastructural features despite minimal nuclear injury of some cells and reduction in glycogen and lipid deposits. Hepatocytes in conventional monolayers appeared flattened and exhibited a spindle-like appearance. Moreover, marked clumping of nuclear chromatin, nucleolar segregation, lysis of the mitochondrial cristae, dilatation of smooth endoplasmic reticulum, depletion of glycogen and lipid stores with loss of intactness of the cell membranes were signs of prominent cellular injury in hepatocytes cultured as monolayers. In addition to maintaining a more in vivo-like morphology, rat hepatocytes cultured as spheroids retained more capacity for secreting albumin than those in conventional monolayers. These observations could suggest that spheroidal cultures allowed better preservation of morphology and function of hepatocytes compared with conventional monolayer culture. The improved morphology and function of hepatocyte cultured as spheroids may provide a more appropriate in-vitro model for hepatocyte research work, especially when long-term culture is crucial