To investigate the cellular mechanisms of pressure-overload cardiac hypertrophy transition to heart failure, we observed time course of changes in morphology and contractile function of cardiomyocytes in transverse abdominal aortic constriction (TAC) rats. Since TAC rats suffered higher stress, body weight had a slower growth rate compared with that of synchronous control rats. Therefore, the left ventricular to body weight ratio produced experimental bias to evaluate the degree of cardiac hypertrophy. Length and width of collagenase-isolated cardiomyocyte were directly measured. Length, width and calculated surface area of cardiomyocyte showed a progressive increase in 8-, 16-, and 20-week TAC rats. The increasing rate of surface area in cardiomyocytes was higher at the middle stage of TAC (from the eighth to sixteenth week). Due to the constraint of fibrosis formation, the increasing rate of surface area in cardiomyocytes was slower at the late stage of TAC (from the sixteenth to twentieth week). The sarcomere length of cardiomyocytes was unchanged, whereas sarcomere numbers were significantly increased in 8-, 16-, and 20-week TAC rats. Shortening amplitude of unloaded contraction in single cardiomyocyte was significantly enhanced in 1-week TAC rats, but not altered in 8-week TAC rats compared with that in the synchronous control rats. On the contrary, unloaded shortening amplitude of single cardiomyocyte was significantly reduced in 16- and 20-week TAC rats. The above results suggest that the reduced shortening amplitude may be associated with intrinsic molecular alterations in hypertrophied cardiomyocytes.
Animals ; Aorta, Abdominal ; Cardiomegaly ; etiology ; physiopathology ; Cell Enlargement ; Constriction ; Hypertension ; complications ; pathology ; physiopathology ; Male ; Myocardial Contraction ; physiology ; Myocytes, Cardiac ; pathology ; physiology ; Rats ; Rats, Sprague-Dawley

OBJECTIVETo explore the possible mechanism of lipopolysaccharide (LPS)-induced cardiomyocyte hypertrophy in rats.

METHODSNeonatal rat cardiomyocytes cultured in vitro were stimulated with 100 µg/L LPS for 1, 4 or 8 h and scanned by atomic force microscopy (AFM) for measurement of the two-dimensional area, three-dimensional surface area and volume of each cell. The total proteins and Na(+)-K(+)-ATPase activity in the cardiomyocytes were determined. The same measurements were also carried out in neonatal rat cardiomyocyte cultures stimulated by 0.5 µmol/L ouabain for 8 h and the total protein levels were measured.

RESULTSFollowing a 8-hour stimulation with LPS, the two-dimensional area, three-dimensional surface area and volume of the single cardiomyocyte became enlarged and the total cellular proteins increased significantly as compared with those in the normal control cells (P < 0.05). LPS treatment for 4 and 8 h resulted in significantly decreased activity of Na(+)-K(+)-ATPase in the cardiomyocytes (P < 0.05). In the cells treated with ouabain for 8 h, the two-dimensional area, three-dimensional surface area, volume of the single cardiomyocyte and the total cellular proteins increased significantly in comparison with the normal control group (P < 0.05).

CONCLUSIONLPS can result in cardiomyocyte hypertrophy in rats possibly in relation to lowered Na(+)-K(+)-ATPase activity in the cardiomyocytes after LPS exposure.

Animals ; Animals, Newborn ; Cell Enlargement ; drug effects ; Cells, Cultured ; Hypertrophy ; chemically induced ; Lipopolysaccharides ; Myocytes, Cardiac ; enzymology ; pathology ; Rats ; Rats, Wistar ; Sodium-Potassium-Exchanging ATPase ; metabolism

OBJECTIVETo demonstrate the inhibitory effect of kappa-opioid receptor activation by U50488H on hypertrophy induced by NE in cultured neonatal rat cardiac myocytes and compare its effect with that of prazosin and propranolol.

METHODSThe cellular proliferation was determined with crystal violet staining. The protein content was assayed with Lowry's method. The cardiomyocytes volumes were measured by computer photograph analysis system. The protein synthesis was assayed with [3H]-lencine incorporation method.

RESULTS(1) NE significantly induced the increase of protein content, [3H]-leucine incorporation and cell size without a concomitant increase in cell number in low serum medium. OThese responses were partially suppressed by prazosin or propranolol alone and completely abolished by both in combination. U50488H significantly inhibited the NE-induced increase of protein content, [3H]-leucine incorporation and cell size. The inhibitory effects of U50488H on NE-induced cardiac hypertrophy were greater than either prazosin or propranolol, but comparable to combination of both.

CONCLUSIONNE, acting via both alpha1- and beta-adrenergic pathway, stimulates myocyte hypertrophy. Stimulating kappa-opioid receptor significantly inhibits NE-induced cardiac hypertrophy, which may be related with alpha1- and beta1-adrenergic pathway.

3,4-Dichloro-N-methyl-N-(2-(1-pyrrolidinyl)-cyclohexyl)-benzeneacetamide, (trans)-Isomer ; pharmacology ; Adrenergic alpha-1 Receptor Antagonists ; pharmacology ; Adrenergic beta-Antagonists ; pharmacology ; Animals ; Animals, Newborn ; Cardiomegaly ; chemically induced ; pathology ; prevention & control ; Cell Enlargement ; drug effects ; Cells, Cultured ; Female ; Male ; Myocytes, Cardiac ; cytology ; Norepinephrine ; Prazosin ; pharmacology ; Propranolol ; pharmacology ; Rats ; Rats, Sprague-Dawley ; Receptors, Opioid, kappa ; agonists

Aquaporin belongs to a highly conserved group of membrane proteins called major intrinsic proteins (MIPs) that facilitate water transport across biological membranes. Aquaporins are membrane water channels that play critical roles in controlling the water content of cells and tissues. We focused on GhPIP1;2 which belongs to the PIP subfamily and GhgammaTIP1 which belongs to the gammaTIP group of the TIP subfamily. Northern blot analysis with gene-specific probes and real-time PCR demonstrated that GhPIP1;2 and GhgammaTIP1 are predominantly expressed during cotton fiber elongation, with the highest expression levels at 5 days post anthesis. The high and preferential expression of GhPIP1;2 and GhgammaTIP1 suggests that they may play important roles in supporting the rapid influx of water into vacuoles during cotton fiber cell expansion. Also, the effects of Ca2+ on aquaporins in salinity-stressed plants were studied. Researchers treated the protoplasts and plasma membrane with NaCl or CaCl2, alone or in combination. Under saline conditions, osmotic water permeability (Pf) values decreased in protoplasts and plasma membrane vesicles, and the same reduction was observed in the PIP1 aquaporin abundance, indicating inhibitory effects of NaCl on aquaporin functionality and protein abundance. Two different actions of Ca2+ were observed. Increase in free cytosolic calcium concentrations associated with stress perception may lead to aquaporin closure, however, the extra-calcium would lead to an upregulation of aquaporins. Meanwhile, experiments have demonstrated HvPIP2;1, one of barley aquaporins, has a higher water and CO2 transport activity. The goal of our plant aquaporin research is to determine the key aquaporin species responsible for water and CO2 transport, and to improve plant water relations, stress tolerance, CO2 uptake or assimilation, and plant productivity.
Aquaporins ; physiology ; Cell Enlargement ; Cotton Fiber ; Gossypium ; metabolism ; physiology ; Photosynthesis ; physiology ; Plant Proteins ; physiology ; Sodium Chloride ; pharmacology ; Stress, Physiological ; physiology

Peroxisome proliferator-activated receptor alpha (PPARalpha) activation in rodents is thought to improve insulin sensitivity by decreasing ectopic lipids in non-adipose tissues. Fenofibrate, a lipid-modifying agent that acts as a PPARalpha agonist, may prevent adipocyte hypertrophy and insulin resistance by increasing intracellular lipolysis from adipose tissue. Consistent with this hypothesis, fenofibrate decreased visceral fat mass and adipocyte size in high fat diet-fed obese mice, and concomitantly increased the expression of PPARalpha target genes involved in fatty acid beta-oxidation in both epididymal adipose tissue and differentiated 3T3-L1 adipocytes. However, mRNA levels of adipose marker genes, such as leptin and TNFalpha, were decreased in epididymal adipose tissue by fenofibrate treatment. Fenofibrate not only reduced circulating levels of free fatty acids and triglycerides, but also normalized hyperinsulinemia and hyperglycemia in obese mice. Blood glucose levels of fenofibrate-treated mice were significantly reduced during intraperitoneal glucose tolerance test compared with obese controls. These results suggest that fenofibrate-induced fatty acid beta-oxidation in visceral adipose tissue may be one of the major factors leading to decreased adipocyte size and improved insulin sensitivity.
3T3 Cells ; Adipocytes/cytology/*drug effects ; Animals ; Antilipemic Agents/*pharmacology ; Blood Glucose ; Body Weight ; Cell Enlargement/*drug effects ; Dietary Fats ; Gene Expression Regulation/drug effects ; Glucose Tolerance Test ; Insulin/blood ; *Insulin Resistance ; Leptin/genetics ; Lipids/blood ; Mice ; Mice, Inbred C57BL ; Mice, Obese ; PPAR alpha/*metabolism ; Procetofen/*pharmacology ; Tumor Necrosis Factor-alpha/genetics

OBJECTIVETo observe the effect of transfection with small interfering RNA (siRNA) targeting connective tissue growth factor (CTGF) on human tubular epithelial hypertrophy induced by high glucose.

METHODSHK-2 cells were cultured in DMEM/F12 medium containing 1 g/L glucose (normal control group), 4.5 g/L glucose (high glucose group), or 1 g/L glucose+3.5 g/L mannitol (iso-osmolar control group). The cells were transfected with pGenesil-1, pGenesil/neg, or pGenesil/siRNA-CTGF and then cultured in DMEM/F12 medium containing 4.5 g/L glucose as the high glucose+blank control group, high glucose+negative control group and high glucose+interference group, respectively. After cell culture for 24, 48 and 96 h, the cells were collected to detect the mRNA and protein levels of CTGF by real-time PCR and Western blotting, respectively. The proliferative activities of the cells were evaluated with MTT assay, and the total cellular protein contents were determined with Bradford method. Flow cytometry was employed to analyzed the cell cycle changes.

RESULTSHigh-glucose significantly up-regulated the CTGF mRNA and protein levels in HK-2 cells. The cell proliferation was inhibited after high-glucose exposure with increased cell percentage in G1 phase and total cellular protein content suggesting cellular hypertrophy. Transfection with siRNA targeting CTGF significantly inhibited high glucose-induced up-regulation of CTGF mRNA and protein and promoted the cell proliferation, resulting also increased cells in S phase and lowered total cellular protein contents.

CONCLUSIONCTGF is an important mediator of high glucose-induced tubular epithelial hypertrophy, and transfection with siRNA targeting CTGF can alleviate the hypertrophy, suggesting the potential value of CTGF-targeted treatment in the management of diabetic nephropathy.

Cell Enlargement ; drug effects ; Cell Line ; Connective Tissue Growth Factor ; genetics ; metabolism ; Epithelial Cells ; pathology ; Glucose ; pharmacology ; Humans ; Hypertrophy ; Kidney Tubules ; pathology ; RNA Interference ; RNA, Messenger ; genetics ; metabolism ; RNA, Small Interfering ; genetics ; Transfection

OBJECTIVETo investigate the mechanism of rosiglitazone (RSG, the activator of peroxisome proliferators activated receptor lambda) for inhibiting endothelin-1 (ET-1)-induced neonatal rat cardiac myocyte hypertrophy and the role of protein kinase C (PKC) and c-fos.

METHODSIn vitro cultured neonatal rat cardiac myocytes were treated with ET-1, phorbol ester (PMA, the PKC activator), ET-1+RSG, ET-1+chelerythrine (che, the PKC inhibitor), PMA+RSG, or without treatment (control), respectively. The effects of RSG on the protein content, (3)H-leucine incorporation, PKC activity and C-fos protein expression were observed in the cardiac myocytes stimulated with ET-1 or PMA.

RESULTSAfter two days of culture, the intracellular protein content in ET-1 group and PMA group were increased by 15% (339-/+15 microg/ml) and 13% (329-/+14 microg/ml) as compared with the control cells (290-/+13 microg/ml), respectively (P<0.01). Compared with the ET-1 group, cells treated with ET-1+10(-8) mol/L RSG, ET-1+10(-7) mol/L RSG, and ET-1+che showed decreased intracellular protein content by 10% (303-/+14 microg/ml, P<0.05), 12% (292-/+11 microg/ml, P<0.05), and 13% (291-/+12 microg/ml, P<0.01), respectively. The intracellular protein content in PMA+10(-7) mol/LRSG group was decreased by 10% (P<0.05) in comparison with the PMA group. RSG inhibited protein synthesis enhancement and increased (3)H-leucine incorporation induced by ET-1 and PMA, and antagonized the effects of ET-1 and PMA in promoting PKC activity and c-fos protein expression in the myocytes.

CONCLUSIONThe inhibitory effect of RSG on ET-1- or PMA-induced myocyte hypertrophy is associated with PKC-c-fos pathway.

Animals ; Animals, Newborn ; Blotting, Western ; Cell Enlargement ; drug effects ; Cells, Cultured ; Dose-Response Relationship, Drug ; Endothelin-1 ; pharmacology ; Hypoglycemic Agents ; pharmacology ; Myocytes, Cardiac ; cytology ; drug effects ; metabolism ; Protein Kinase C ; metabolism ; Proto-Oncogene Proteins c-fos ; biosynthesis ; Rats ; Rats, Sprague-Dawley ; Signal Transduction ; drug effects ; Tetradecanoylphorbol Acetate ; pharmacology ; Thiazolidinediones ; pharmacology

TGF-beta1-induced glomerular mesangial cell (GMC) injury is a prominent characteristic of renal pathology in several kidney diseases, and a ternary protein complex consisting of PINCH-1, integrin-linked kinase (ILK) and alpha-parvin plays a pivotal role in the regulation of cell behavior such as cell proliferation and hypertrophy. We report here that PINCH-1-ILK-alpha-parvin (PIP) complex regulates the TGF-beta1-induced cell proliferation and hypertrophy in cultured rat GMCs. When GMCs were treated with TGF-beta1 for 1, 2 and 3 days, the PIP complex formation was up-regulated after 1 day, but it was down-regulated on day 2. Cell numbers were significantly elevated on day 2, but dramatically decreased on day 3. In contrast, a significant increase in cellular protein contents was observed 3 days after TGF-beta1-treatment. TGF-beta1 induced early increase of caspase-3 activity. In GMCs incubated with TGF-beta1 for 2 days, cytosolic expression of p27(Kip1) was dramatically reduced, but its nuclear expression was remarkably elevated. A significantly decreased expression of phospho-Akt (Ser 473) was observed in the cells treated with TGF-beta1 for 1 day. TGF-beta1 induced early increase of phospho-p27(Kip1) (Thr 157) expression with subsequent decrease, and similar responses to TGF-beta1 were observed in the p38 phosphorylation (Thr 180/Thr 182). Taken together, TGF-beta1 differently regulates the PIP complex formation of GMCs in an incubation period-dependant fashion. The TGF-beta1-induced up- and down-regulation of the PIP complex formation likely contributes to the pleiotropic effects of TGF-beta1 on mesangial cell proliferation and hypertrophy through cellular localization of p27(Kip1) and alteration of Akt and p38 phosphorylation. TGF-beta1-induced alteration of the PIP complex formation may be importantly implicated in the development and progression of glomerular failure shown in several kidney diseases.
Animals ; *Cell Enlargement ; *Cell Proliferation ; Cells, Cultured ; Cyclin-Dependent Kinase Inhibitor p27/metabolism ; Cytoskeletal Proteins/*metabolism ; DNA-Binding Proteins/*metabolism ; Male ; Mesangial Cells/drug effects/*physiology ; Microfilament Proteins/*metabolism ; Phosphorylation ; Protein-Serine-Threonine Kinases/*metabolism ; Rats ; Rats, Sprague-Dawley ; Signal Transduction ; Transforming Growth Factor beta1/*pharmacology ; p38 Mitogen-Activated Protein Kinases/metabolism

OBJECTIVETo study large-scale expansion of SD (Sprague-Dawley) rat's osteoblasts in suspension culture in a rotating wall vessel bioreactor (RWVB).

METHODSThe bioreactor rotation speeds were adjusted in the range of 0 to 20 rpm, which could provide low shear on the microcarriers around 1 dyn/cm2. The cells were isolated via sequential digestions of neonatal (less than 3 days old) SD rat calvaria. After the primary culture and several passages, the cells were seeded onto the microcarriers and cultivated in T-flask, spinner flask and RWVB respectively. During the culture period, the cells were counted and observed under the inverted microscope for morphology every 12 h. After 7 days, the cells were evaluated with scanning electron microscope (SEM) for histological examination of the aggregates. Also, the hematoxylin-eosin (HE) staining and alkaline phosphatase (ALP) staining were performed. Moreover, von-Kossa staining and Alizarin Red S staining were carried out for mineralized nodule formation.

RESULTSThe results showed that in RWVB, the cells could be expanded by more than ten times and they presented better morphology and vitality and stronger ability to form bones.

CONCLUSIONSThe developed RWVB can provide the culture environment with a relatively low shear force and necessary three-dimensional (3D) interactions among cells and is suitable for osteopath expansion in vitro.

Animals ; Bioreactors ; Cell Culture Techniques ; instrumentation ; Cell Enlargement ; Culture Media ; Glucose ; metabolism ; Hydrogen-Ion Concentration ; Lactic Acid ; metabolism ; Osmolar Concentration ; Osteoblasts ; cytology ; metabolism ; ultrastructure ; Rats ; Rats, Sprague-Dawley

Cardiac hypertrophy is an adaptive process to an increased hemodynamic overload. However, the adaption may lead to the fragility of myocardium facing pathological stimuli. In the present study, experiments were designed to explore the susceptibility of hypertrophic myocardiocytes to apoptotic stimuli and the role of protein kinase Cdelta (PKCdelta) during the transition from hypertrophy to apoptosis. Endothelin-1 (ET-1)-treated cardiomyocytes were used as model of cardiac hypertrophy. Angiotensin II (Ang II) was used as an apoptotic stimulus. Cell surface area was measured to determine the extent of hypertrophy. The apoptotic rate in cardiomyocytes was detected by Hoechst 33258. (1) Cell surface area was increased by 42.5% and 67.3% following 1 nmol/L and 10 nmol/L ET-1 treatment, respectively, as compared with serum-free cultured myocytes. So the mildly and moderately hypertrophic myocyte models were set up. (2) Apoptotic rates in serum-free cultured, mildly and moderately hypertrophic myocytes after Ang II treatment were (15.54+/-1.32) %, (20.65+/-1.40) % and (29.33+/-3.52) %, respectively. It is suggested that hypertrophic myocytes are more susceptive to apoptotic stimulus. (3) Rottlerin, a specific inhibitor of PKCdelta depressed apoptotic rates induced by Ang II to (15.88+/-2.25) % in mildly hypertrophic myocytes and to (15.01+/-1.37) % in moderately hypertrophic myocytes; but rottlerin did not affect apoptotic rate induced by Ang II in serum-free cultured myocytes. These results suggest that inhibition of PKCdelta can reduce Ang II-induced apoptosis of hypertrophic cardiomyocytes and that PKCdelta is possibly involved in the apoptotic process of hypertrophic cardiomyocytes.
Angiotensin II ; pharmacology ; Animals ; Animals, Newborn ; Apoptosis ; drug effects ; physiology ; Cardiomegaly ; pathology ; physiopathology ; Cell Enlargement ; drug effects ; Endothelin-1 ; pharmacology ; Heart Failure ; physiopathology ; Myocytes, Cardiac ; cytology ; pathology ; Primary Cell Culture ; Protein Kinase C-delta ; physiology ; Rats ; Rats, Sprague-Dawley