Establishment and characterization of a rat pancreatic stellate cell line by spontaneous immortalization

AIM: Activated pancreatic stellate cells (PSCs) have been implicated in the pathogenesis of pancreatic fibrosis and inflammation. Primary PSCs can be subcultured only several times because of their limited growth potential. A continuous cell line may therefore be valuable in studying molecular mechanisms of these pancreatic disorders. The aim of this study was to establish a cell line of rat PSCs by spontaneous immortalization.METHODS: PSCs were isolated from the pancreas of male Wistar rats, and conventional subcultivation was performed repeatedly. Telomerase activity was measured using the telomere repeat amplification protocol. Activation of transcription factors was assessed by electrophoretic mobility shift assay.Activation of mitogen-activated protein (MAP) kinases was examined by Western blotting using anti-phosphospecific antibodies. Expression of cytokine-induced neutrophil chemoattractant-1 was determined by enzyme immunoassay.RESULTS: Conventional subcultivation yielded actively growing cells. One clone was obtained after limiting dilution,and designated as SIPS. This cell line has been passaged repeatedly more than 2 years, and is thus likely immortalized.SIPS cells retained morphological characteristics of primary,culture-activated PSCs. SIPS expressed α-smooth muscle actin, glial acidic fibrillary protein, vimentin, desmin, type Ⅰ collagen, fibronectin, and prolyl hydroxylases. Telomerase activity and p53 expression were negative. Proliferation of SIPS cells was serum-dependent, and stimulated with platelet-derived growth factor-BB through the activation of extracellular signal-regulated kinase. Interleukin-1β activated nuclear factor-κB, activator protein-1, and MAP kinases.Interleukin-1β induced cytokine-induced neutrophil chemoattractant-1 expression through the activation of nuclear factor-κB and MAP kinases.CONCLUSION: SIPS cells can be useful for in vitro studies of cell biology and signal transduction of PSCs.

Influencing factors of rat small intestinal epithelial cell cultivation and effects of radiation on cell proliferation

INTRODUCTIONCrypt epithelial cells in normal small intestineproliferate at a high speed. But they are verydifficult to culture in vitro and passage stably. A lotof studies have been done[1-16]. Some domestic labsisolated and cultured crypt cells from embryonalintestines and aseptic animal intestine, but failed.We introduced normal rat epithelial cell line-IEC-6from the USA and its living condition for stablepassage was successfully established after trials. Thecell line was testified to be the small intestinalepithelial cell by electron microscopy,immunihistochemistry and enzymatic histoch-emistry. It has been applied to some relatedresearch work[17-21]. It was found that manyfactors were involved in the culture system. Ourpresent study focuses on the culture method and theinfluencing factors on IEC-6.

Thermal Diversities of Two Na^+/H^+ Exchanges in Guinea Pig Red Cells

Objective\ To test the effect of hypothermia on Na+/H+ exchange, activated by shrinkage and cytoplasmic acidosis. Method\ Amiloride-sensitive Na+ influx in guinea pig red cells was traced with isotope 22Na and intracellular Na+ concentration was measured by emission flame photometry. Result\ Amiloride-sensitive Na+ influx decreased linearly as a function of temperatures (about 37℃) in shrunken cells, but increased in acidified cells. The up-regulation of acid-induced Na+/H+ exchange by elevated temperature was enhanced by hypo-osmolarity. Less sensitivity of intracellular H+ site at 41℃ may be the mechanism for the inhibition of shrinkage-induced Na+/H+ exchange by elevated temperature. Heating-mediated explosive increase in the activity of acid-induced Na+/H+ exchange may be due to enhanced extracellular Na+ sensitivity and lower intracellular pH caused by acidic metabolites. Acid-induced Na+/H+ ewxchange contributes to cytoplasmic Na+ accumulation. Conclusion\ These two modes of Na+/H+ exchange with different response to elevated temperature may play different roles in the cellular pathogenesis of heatstroke.

Transplantation of corneal stem cells cultured on amniotic membrane for corneal burn: experimental and clinical study

OBJECTIVE: To investigate the proliferation and differentiation of cultured corneal stem cells and determine the effect of corneal stem cells cultured on amniotic membranes on the limbal area for treating corneal burns. METHODS: The proliferation and differentiation of corneal stem cells in vitro had been examined using colony-forming efficiency and immunohistochemistry. The stem cells had been cultured on amniotic membranes and transplanted to the limbal area for treating corneal burns. RESULTS: Corneal stem cells had a high proliferation capacity in primary and first passage, cytokeratin 3 was not expressed in primary culture but partly in first passage. The stem cells could proliferate to form cell layer on an amniotic membrane. When transplanted, stem cells could survive on limbus. After transplantation, ocular inflammation resolved, the cornea re-epithelialized, the stromal opacity reduced, the superficial neovascularity was lessened and the conjunctival fornix re-established. CONCLUSIONS: Ocular surface conditions could be improved by allograft of corneal stem cells cultured on amniotic membranes.

Thansgenic peanut plants obtained by particle bombardment via somatic embryogenesis regeneration system

After pre-culture and treatment of osmosis, cotyledons of immature peanut (Arachis hypogaea L.) zygotic embryos were transformed via particle bombardment with a plasmid containing a chimeric hph gene conferring resistance to hygromycin and a chimeric intron-gus gene. Selection for hygromycin resistant calluses and somatic embryos was initiated at 10th d post-bombardment on medium containing 10-25 mg/L hygromycin. Under continuous selection, hygromycin resistant plantlets were regenerated from somatic embryos and were recovered from nearly 1.6% of the bombarded cotyledons. The presence and integration of foreign DNA in regenerated hygromycin resistant plants was confirmed by PCR (polymerase chain reaction) for the intron-gus gene and by Southern hybridization of the hph gene. GUS enzyme activity was detected in leaflets from transgenic plants but not from control, non-transformed plants. The production of transgenic plants are mainly based on a newly improved somatic embryogenesis regeneration system developed by us.

Culture of osteoblasts on bio-derived bones

OBJECTIVE: To study the effect of bio-derived bones, as substitutes of autogenous bone grafts and demineralized cadaver bones, on the attachment, spreading and proliferation of isolated osteoblasts. METHODS: Osteoblasts were isolated from the calvaria of a fetal rabbit through sequential collagenase digestion. In the attachment study, the osteoblasts labeled with 3H-leucine were incubated with the bio-derived bone materials in sterile microcentrifugable tubes for 15, 90 and 180 minutes, and 24 hours, respectively. The attached cells were collected and the radioactivity was measured with liquid scintillation spectrometry. In the proliferation study, the osteoblasts were cultured with the bio-derived bone materials for 24 hours and 3H-thymidine was added during the last 2 hours of the incubation. The attached cells were collected and the radioactivity was measured with liquid scintillation spectrometry. Osteoblasts were seeded on the bone graft materials for 60 or 120 minutes, 24 or 48 hours, and 3 or 7 days, then the co-culture was processed for scanning electron microscopy to observe the interaction of osteoblasts and the bio-derived bone materials. RESULTS: Osteoblasts attached to the bio-derived bone materials in a time-dependent manner. There were significantly (P

Optimization of transfection efficiency of small interfering RNA in purified human prolactinoma cells

Background Control of hypersecretion of certain hormones is one of the key targets in the treatment of pituitary adenomas. RNA interference has been shown to inhibit protein expression, and thus it may represent a promising method for the treatment of pituitary adenomas. In the present study, transfection efficiency of small interfering RNA （siRNA） was optimized in human prolactinoma cells. Methods First, a method was optimized to extract highly purified human prolactinoma cells in vitro. The extracted cells were verified to retain the physiological features of prolactin （PRL） secretion. Second, three conditions for siRNA transfection were tested by the evaluation of transfectfon efficiency and cell viability. The proper transfection condition was verified for human prolactinoma cells. Third, the siRNA for prolactin was transfected into the human prolactinoma cells, and the suppression of PRL mRNA was evaluated by quantitative real-time reverse transcription-PCR. Results The siRNA of 100 pmol with Lipofectamine 2000 of 5 μl for 1×10^6 cells was proved preferable, with transfection efficiency being 53.3% and cell viability being 69.7%. In the preliminary experiment the siRNA against PRL decreased the mRNA of PRL by 34.0%. Conclusion It is possible to inhibit hormone hypersecretion by RNA interference, that may eventually enable therapeutic siRNA drugs developed.