Apoptotic and necrotic effects of pectic acid on rat pituitary GH3/B6 tumor cells

Pectin is composed of complex polysaccharides that can inhibit cancer metastasis and proliferation with no evidence of toxicity. In the present study, the apoptotic and necrotic effects of pectic acid [PA] on the rat pituitary GH3/B6 tumor cells has been investigated. GH3/B6 cells were cultured in the Ham's F12 medium enriched with 15% horse serum and 2.5% fetal bovine serum for 3 days. Then, they were treated by various amounts of PA in different periods [6, 24 and 48 hours]. Bromocriptine was used as positive control and the cell viability was detected by MTT test. The nuclear morphology of cells was explored by florescent stains including acridine orange [AO]/ethidium bromide [EB]. In addition, percentages of apoptotic and necrotic cells were studied with triphosphate nick-end labeling [TUNEL] assay, cell cycle analysis and propidium iodide [PI] staining. Long-term incubation with PA results in increased cell death and DNA damage as detected by MTT assay and AO/EB staining. TUNEL assay showed that PA [100 micro g/ml to 1 mg/ml] could induce apoptosis in a dose-dependent manner, while higher concentrations of PA [2.5 and 5 mg/ml] induced necrosis which was confirmed by PI staining. Furthermore, cell cycle analysis indicated that PA induced sub G1 events, and DNA fragmentation was also correlated with the number of the apoptotic cells. It can be concluded that PA is responsible for apoptosis in the rat pituitary tumor cells. Therefore, one may suggest that this group of polysaccharides can be used in treatment of pituitary tumors

Effect of basic fibroblast growth factor on cardiomyocyte differentiation from mouse embryonic stem cells

To investigate the effect of basic fibroblast growth factor [bFGF] on the differentiation of embryonic stem cells [ESCs] into early cardiomyocytes. Embryoid bodies [EBs] were produced from mouse ESC line [Royan B1] in hanging drops and cultured for 5 days as suspension. During the first 2 days of suspension, the EBs of the experimental group were treated with 10 ng/ml of bFGF and subsequently plated onto gelatin-coated tissue culture dishes [day 7]. The differentiated cells were evaluated pharmacologically, by immunocytochemistry, and so forth. The study was carried out in the Department of Stem Cells, Royan Institute, Tehran, Iran in 2005. The beating frequency in the bFGF treated EBs was less than that in the control group. In addition, the beating in the EBs of the experimental group, treated with isoprenaline and phenylephrine, was only more than 7+3 days in comparison to the control group. The response of the EBs to carbachol was more in the bFGF group than 7+14 days. In all the stages of development, the beating cells in the EBs of both groups expressed beta-actinin, myosin light chain isoform 2V, cardiac alpha-myosin heavy chain [alpha-MHC], and cardiac beta-myosin heavy chain [beta-MHC]. Nonetheless, during 7+3 days, the last 2 genes were more advanced in the bFGF group. The atrial natriuretic factor was also expressed at a late stage in both groups. Basic fibroblast growth factor can only promote the early maturation of ESC-derived cardiomyocytes in terms of chronotropic characteristics and expression of cardiac alpha-MHC and beta-MHC