Current status and challenges for cell-cultured milk technology: a systematic review

Cellular agriculture is an innovative technology for manufacturing sustainable agricultural products as an alternative to traditional agriculture.While most cellular agriculture is predominantly centered on the production of cultured meat,there is a growing demand for an understanding of the production techniques involved in dairy products within cellular agriculture.This review focuses on the current status of cellular agriculture in the dairy sector and technical challenges for cell-cultured milk production.Cellular agriculture technology in the dairy sector has been classified into fermentation-based and animal cell culture-based cellular agriculture.Currently,various companies synthesize milk components through precision fermentation technology.Nevertheless,several startup companies are pursuing animal cell-based technology,driven by public concerns regarding genetically modified organisms in precision fermentation technology.Hence,this review offers an up-to-date exploration of animal cell-based cellular agriculture to produce milk components,specifically emphasizing the structural,functional,and productive aspects of mammary epithelial cells,providing new information for industry and academia.

Sequential extraction of RNA,DNA and protein from cultured cells of the same group

BACKGROUND Efficient extraction of nucleic acids and proteins(ENAP)from cells is a prerequisite for precise annotation of gene function,and has become laboratory routine for revealing the mysteries of life.However,cell samples are often from different culture dishes,resulting in inevitable experimental errors and sometimes poor repeatability.AIM To explore a method to improve the efficiency of ENAP,minimizing errors in ENAP processes,enhancing the reliability and repeatability of subsequent experimental results.METHODS A protocol for the sequential isolation of RNA,DNA,and proteins from the same cultured HepG2 cells using RNAzol reagent is presented here.The first step involves culturing HepG2 cells to the exponential phase,followed by the sequential isolation of RNA,DNA,and proteins from the same cultured cells in the second step.The yield of nucleic acids and proteins is detected in the third step,and their purity and integrity are verified in the last step.RESULTS The procedure takes as few as 3-4 d from the start to quality verification and is highly efficient.In contrast to the existing kits and reagents,which are primarily based on independent isolation,this RNAzol reagent-based method is characterized by the sequential isolation of RNA,DNA,and proteins from the same cells,and therefore saves time,and has low cost and high efficiency.CONCLUSION The RNA,DNA,and proteins isolated using this method can be used for reverse transcription-polymerase chain reaction,polymerase chain reaction,and western blotting,respectively.

Repetitive administration of cultured human CD34+cells improve adenine-induced kidney injury in mice

BACKGROUND There is no established treatment to impede the progression or restore kidney function in human chronic kidney disease(CKD).AIM To examine the efficacy of cultured human CD34+cells with enhanced proliferating potential in kidney injury in mice.METHODS Human umbilical cord blood(UCB)-derived CD34+cells were incubated for one week in vasculogenic conditioning medium.Vasculogenic culture significantly increased the number of CD34+cells and their ability to form endothelial progenitor cell colony-forming units.Adenineinduced tubulointerstitial injury of the kidney was induced in immunodeficient non-obese diabetic/severe combined immunodeficiency mice,and cultured human UCB-CD34+cells were administered at a dose of 1×106/mouse on days 7,14,and 21 after the start of adenine diet.RESULTS Repetitive administration of cultured UCB-CD34+cells significantly improved the time-course of kidney dysfunction in the cell therapy group compared with that in the control group.Both interstitial fibrosis and tubular damage were significantly reduced in the cell therapy group compared with those in the control group(P<0.01).Microvasculature integrity was significantly preserved(P<0.01)and macrophage infiltration into kidney tissue was dramatically decreased in the cell therapy group compared with those in the control group(P<0.001).CONCLUSION Early intervention using human cultured CD34+cells significantly improved the progression of tubulointerstitial kidney injury.Repetitive administration of cultured human UCB-CD34+cells significantly improved tubulointerstitial damage in adenine-induced kidney injury in mice via vasculoprotective and anti-inflammatory effects.

Expression of Tissue Transglutaminase in Cultured Bovine Trabecluar Meshwork Cells

Summary: To study whether cultured bovine trabecluar meshwork cells (BTMC) are capable of expressing tTG in protein and at mRNA level, BTMC were cultured in vitro and passaged three times, then the cells were transferred onto or cultured on sterile cover or submitted to isolation of RNA with Trizol, and the expression of tTG was detected by immunohistochemical technique and reverse transcription polymerase chain reaction (RT-PCR) respectively. Our results showed that tTG immunostaining was positive in the cytoplasm and rarely in the nucleus of cultured BTMC. No immunostaining was seen in the negative control. Moreover, a single RT-PCR amplified product whose sequence and size were in accordance with our known parameters was obtained. The expression of tTG in cultured BTMC was confirmed in protein and at mRNA level. BMTC is available more readily for the investigation of the relationship between tTG and primary open-angle glaucoma.

Cultured meat from muscle stem cells: A review of challenges and prospects

Growing muscle tissue in culture from animal stem cells to produce meat theoretically eliminates the need to sacrifice animals. So-called ＂cultured＂ or ＂synthetic＂ or ＂in vitro＂ meat could in theory be constructed with different characteristics and be produced faster and more efficiently than traditional meat. The technique to generate cultured muscle tissues from stem cells was described long ago, but has not yet been developed for the commercial production of cultured meat products. The technology is at an early stage and prerequisites of implementation include a reasonably high level of consumer acceptance, and the development of commercially-viable means of large scale production. Recent advancements in tissue culture techniques suggest that production may be economically feasible, provided it has physical properties in terms of colour, flavour, aroma, texture and palatability that are comparable to conventional meat. Although considerable progress has been made during recent years, important issues remain to be resolved, including the characterization of social and ethical constraints, the fine-tuning of culture conditions, and the development of culture media that are cost-effective and free of animal products. Consumer acceptance and confidence in in vitro produced cultured meat might be a significant impediment that hinders the marketing process.

Experimental study of bioartificial liver with cultured human liver cells

AIM To establish an extracorporeal bioartificial liver support system (EBLSS) using cultured human liver cells and to study its support effect for fulminant hepatic failure (FHF).METHODS The liver support experiment of EBLSS consisting of aggregates cultured human liver cells, hollow fiber bioreactor, and circulation unit was carried out in dizhepatic dogs.RESULTS The viability of isolated hepatocytes and nonparenchymal liver cells reached 96%. These cells were successfully cultured as multicellular spheroids with synthetic technique. The typical morphological appearance was retained up to the end of the artificial liver experiment. Compared with the control dogs treated with EBLSS without liver cells, the survival time of artificial liver support dogs was significantly prolonged. The changes of blood pressure, heart rate and ECG were slow. Both serum ammonia and lactate levels were significantly lowered at the 3rd h and 5th h. In addition, a good viability of human liver cells was noted after 5 h experiment.CONCLUSION EBLSS playing a metabolic role of cultured human hepatocytes, is capable of compensating the function of the liver, and could provide effective artificial liver support and therapy for patients with FHF.

Cloning of the non-structural gene 3 of hepatitis C virus and its inducible expression in cultured cells

AIM To study the inducible expression of hepatitis C virus ns3 gene (HCV ns3) in eukaryotic cells.METHODS The ns3 gene was obtained from plasmid pBns3 by polymerase chain reaction and inserted into the cloning vector pGEM-T. Then, the ns3 was subcloned into the vector pMSG to generate dexamethasone (DM)-inducible expression plasmid pMSG-ns3. CHO cells were transfected by pMSG-ns3 using calcium phosphate precipitation method and cultivated for 12 h-24 h. The transfected cells were induced with DM and the transient expression of NS3 protein was analyzed by ELISA and Western-blot methods.RESULTS After treated with 3×10-8mol/ L DM, the expression of NS3 was observed in the transfected CHO cells. A slightly higher level of NS3 was shown along with the time of DM treatment.CONCLUSION The inducible expressing vector pMSG-ns3 might be helpful for further studies of the characteristics of the ns3 gene in vivo.

Transplantation of primary cultured embryonic mesencephalic neural precursor cells for treating Parkinsonian rats

BACKGROUND： Choosing proper donor cells is one of keys in experimental and clinical studies on cell replacement therapy （CRT） for treating Parkinson disease （PD）. Embryonic mesencephalic precursor cells （MPCs） can stably differentiate into dopaminergic neuron after in vitro proliferated culture. As compared with embryonic stem cell and neural stem cell strains, cell composition of embryonic MPCs after primary culture is also the most close to that of embryonic mesencephalic ventral cell suspension without proliferated culture. Successful experience accumulated in the latter suggests that primary cultured embryonic MPCs might be the most potential donor cells in clinical application with CRT for treating PD so far. OBJECTIVE： To investigate the feasibility of primary cultured embryonic precursor cells cultured primarily as donor cells in CRT for treating PD in rats. DESIGN ： A randomized and controlled trial taking SD rats as experimental animals.SETTING： Department of Neurosurgery, Huashan Hospital Affiliated to Fudan University.MATERIALS： This experiment was carried out at the Institute of Neuroscience, Shanghai Institute for Biological Science, Chinese Academy of Sciences from July 2003 to June 2004. Totally 26 female SD rats, with body mass of 200 to 220 g, were provided by Shanghai Experimental Animal Center of Chinese Academy of Sciences. METHODS ： Stereotaxic injection of 6-hydroxydopamine into the medial forebrain bundle were perfored to develop PD model rat. Among 26 SD rats, 20 rats achieved a more than 5 turns/min in apomorphine induced rotation test, reaching the standard of PD model rats. Immunohistochemical detection was performed on 1 out of 20 model rats after execution, and the other 19 rats were randomly divided into control group （n=5）, sham transplantation group （n=5）and cell grafted group （n=9）. Primary cultured E12 MPC cell suspension （1.2×10^11 L^-1）were used as donor cells. 4μL primary cultured E12 MPC cell suspension prepared freshly was injected into the lesioned corpus striatum of rats in cell grafted group, and 4μL D-Hank＇s solution was injected in sham transplantation group in the same way. There was no injection in control group. Apomorphine-induced rotation rate of PD rats were recorded respectively in cell grafted group and sham transplantation group pre-operation （initial value） and at postoperative 2, 4, 6 and 16 weeks. Apomorphine-induced rotation rate of PD rats was recorded in control group at postoperative 2 months （initial value） and following 2,4,6 and 16 weeks. To determine TH antigen with immunohistological ABC method （DAB developing） at 6 months post-transplantation to investigate the differentiation and survival of donor cells in the host body.MAIN OUTCOME MEASURES： Apomorphine-induced rotation behavior before and after transplantation and the survival and differentiation of implanted cells in the host body at 6 months post-transplantation. RESULTS： Among 19 model rats, one rat died after transplantation respectively in the cell grafted group and sham transplantation group; finally 17 model rats entered the stage of result analysis. Relative apomorphine-induced rotation rate was significantly decreased in the cell grafted group as compared with that before transplantation , with significant difference （P 〈 0.01 .P 〈 0.05）;the mean value of relative apomorphine-induced rotation rate was significantly decreased at postoperative 16 weeks in cell grafted group as compared with that of corresponding relative rotation rate in control group , also with significant difference （P 〈 0.05）.Immunohistological results showed that donor cells could differentiate into large and multi-polar dopaminergic neurons in the host body. CONCLUSION ： Primary cultured embryonic MPCs can be used as the donor cells in CRT for treating PD.

A study of gentamicin injury mechanisms using cultured mouse cochlear spiral ganglion cells

Objective To study gentamicin injury mechanisms using postnatal mouse cochlear spiral gangcells （SGC）. Methods SGCs were isolated using a combinatorial approach of enzymatic digestion and mechanical separation from P2 - 6 Kunming mouse cochleae. After 4 days, cultured SGCs were fixed with 4% paraformaldehyde at room temperature for immunocytochemical examination using the methods of S-P and the monoclonal antibody against mouse neurofilament protein （Neurofilament-68/200Kda, NF-L＋ H）. SGCs were randomly divided into a blank control group and three gentamicin treatment groups （medium gentamicin concentration at 50 mg/L, 100 mg/L and 150 mg/L respectively）, SGCs were collected and examined under a transmission electron microscope after being cultured for 48 h. Results SGC primary culture was successful. SGC cytoplasm and neurites were dyed brownish yellow by the monoelonal mouse neurofilament protein antibody. SGCs showed classical bipolar neuron appearance. Under the transmission electron microscope,.gentamicin treated SGCs showed morphological features different compared to those in the blank control group, which might indicate apoptosis. Conclusion Our results indicate that gentamicin has direct toxic effects on cochlear SGCs in mice and the injury mechanism is closely related with apoptosis. Damage to mitochor, dria may play an important role in the process.

Manganese enhances the expression of the manganese superoxide dismutase in cultured primary chick embryonic myocardial cells

In the present study, the effect of manganese（Mn） on antioxidant status and the expression of the manganese superoxide dismutase（MnSOD） gene in cultured primary myocardial cells collected from the chick embryos was investigated. The hypothesis that Mn supplementation would enhance the expression of MnSOD in cultured primary myocardial cells of chick embryos was tested. Eggs collected from Mn-depleted Arbor Acres laying breeder hens were incubated for 10 days and then myocardial cells were isolated and cultivated for 8 days. The embryonic myocardial cells on day 6 were treated with Mn in the cell culture medium at different time points when the proportion of cells showing spontaneous contraction was over 95% after the 3-day primary culture. A completely randomized design involving a 3 Mn levels（0, 0.5 and 1.0 mmol L^（-1））×3 incubation time points（12, 24 and 48 h） factorial arrangement of treatments（n=6） was used in the current experiment. The results showed that MnSOD activity and m RNA expression level were induced by Mn and increased with incubation time, which supported the hypothesis that Mn would enhance the expression of the MnSOD gene, and thus might protect myocardial cells from oxidative stress during the chick embryonic development.

THE LOCALIZATION OF ADRENOMEDULLIN IN RAT KIDNEY TISSUE AND ITS INHIBITORY EFFECT ON THE GROWTH OF CULTURED RAT MESANGIAL CELLS

OBJECTIVE: To observe the localization of adrenomedullin (AM) in rat kidney tissue and its inhibitory effect on the growth of cultured rat mesangial cells (MsC). METHODS: A monoclonal antibody against AM developed by our laboratory was used to detect the localization of AM protein in rat kidney tissue by avidin-biotin complex immunohistochemistry. The expressions of AM and its receptor CRLR mRNA on cultured glomerular epithelial cells (GEC) and MsC were investigated by Northern blot assay, and the possible effect of AM secreted by GEC on MsC proliferation was observed using [3H]thymidine incorporation as an index. RESULTS: A specific monoclonal antibody against AM was succesfully developed. AM was immunohistochemically localized mainly in glomeruli (GEC and endothelial cells), some cortical proximal tubules, medullary collecting duct cells, interstitial cells, vascular smooth muscle cells and endothelial cells. Northern blot assay showed that AM mRNA was expressed only on cultured GEC, but not on MsC, however, AM receptor CRLR mRNA was only expressed on MsC. GEC conditioned medium containing AM can inhibit MsC growth and AM receptor blocker CGRP8-37 may partially decreased this inhibitory effect. CONCLUSION: AM produced by GEC inhibits the proliferation of MsC, which suggests that AM as an important regulator is involved in glomerular normal physiological functions and pathologic processes.

Hexabromocyclododecane-induced Genotoxicity in Cultured Human Breast Cells through DNA Damage

To investigate the genotoxicity and reveal the potential toxicological mechanisms of Hexabromocyclododecane （HBCD）, human breast cells HBL-100 were exposed to a sequence of HBCD concentrations （0, 5, 10, and 50 mg/L） for 24 h. With a series of zymology and molecular biology methods, we found that HBCD induced dose-dependent oxidative stress on HBL-100 DNA. As revealed in q RT-PCR, activated prognostic factor ATM down-regulated tumor suppressor gene BRCA1 and prompted DNA repair genes h OGG1 and h MTH1 expression in lower concentrations of HBCD （〈 10 mg/L）. However, DNA repair were inhibited as well as cell proliferation rate by higher concentrations of HBCD （50 mg/L）. The results inferred that the genotoxicity of HBCD was dose-dependent and related to DNA repair pathway.

Determinants of PHGPx Expression in a Cultured Endothelial Cell Line

Selenoprotein biosynthesis may not only be affected by the availability of selenium and the transcription rate of pertinent genes but also by the activity of components of the selenocysteine incorporation complex, SelA, B, C, or D. Incorporation of selenocysteine into selenoproteins requires a complex co-translational mechanism guaranteeing the correct recoding of the termination codon TGA as selenocysteine codon. A particular tRNASer(Sec) is enzyrnatically transformed by selenophosphate into tRNAsec which recognizes the UGA codon by means of a specific elongation factor (SelB) and a peculiar mRNA secondary structure. Selenophosphate is formed from selenide and ATP by the SelD gene product, selenophosphate synthase (SelD). To further elucidate the biological role of phospholipid hydroperoxide GPx (PHGPx), we transformed cells with a heterologous (pig) PHGPx gene and/or an additional (human) SelD gene and studied the behaviour of these cells under selenium depletion and repletion. Transfection of the endothelial cell line ECV 304 with either PHGPx cDNA or SelD cDNA did not result in a substantial increase of PHGPx activities, independent of selenium supply. However, cells co-trans fected with both, PHGPx and SelD cDNA, expressed significantly higher PHGPx activlty. This effect was much more pronounced under selenium limiting conditions. The enhanced PHGPx activity correlated with two functional pararneters, increased capability to reduce hydroperoxides and less sensitivity against H2O2-induced cytotoxicity. Thus, the ECV cells, stably transfected with PHGPx and SelD cDNA, provide a model to specifically investigate the role of PHGPx in endothelial cell function

Changes of peroxide dismutase activity and malondialdehyde level in the smooth muscle cells of human fetal aorta cultured in vitro by low density lipoprotein conditional medium

Here are reported the changes of superoxide dismutase(SOD)activity andmalondialdehyde(MDA)in the smooth muscle cells of human fetal aorta cultured in vitro with lowdensity lipoprotein(LDL)conditional medium.The results showed that a single concentration of hu-man LDL(50μg/ml)stimulated proliferation of smooth muscle cells,and the SOD activityof the cells in the experimental group was higher,from the first to the fifth cultured day whenthe cells had a active proliferation,than that of the control cells.This suggests that LDL might in-duce the increase of SOD activity.At the seventh day,as the cells were in inactive proliferation,SOD activity was low and the difference was significant as compared with that at the fifth day ofthe same group.This also indicates that the SOD activity may be related to the cell proliferation.MDA level within the cells of the esperimental group was lowered with the cell active proliferationand the increase of SOD activity,but when the cells were in inactive proliferation and the SOD ac-tivity decreased,it will remained low.

Antagonistic Effects of Tranilast on Proliferation and Collagen Synthesis Induced by TGF-β_2 in Cultured Human Trabecular Meshwork Cells

Whether tranilast had antagonistic effect on proliferation inhibition and collagen synthesis promotion induced by TGF-β 2 in cultured human trabecular meshwork cells was investigated. Suspension of 1×104 cultured human trabecular meshwork cells of 3—5 passage was distributed in each well of a 96-well disk and divided into control group and experimental group. After 24 h, 0 μg/ml (control), 12.5 μg/ml, 25 μg/ml, 50 μg/ml tranilast with 3.2 ng/ml TGF-β 2 were added into the incubation medium. Another 24 h later, proliferation and collagen synthesis in cultured human trabecular meshwork cells were examined respectively by using tetrazolium-based semiautomated colormetric (MTT) assay and 3H-proline incorporation with liquid scintillation technique. The results showed absorbance (A) values of the experimental groups were 0.9036±0.3017, 1.1361± 0.1352, 1.2457±0.1524 according to the different concentrations of tranilast, and 0.8956± 0.1903 of the control group. In comparison with the control group, 25 μg/ml (q'=3.23, P< 0.05), 50 μg/ml (q'=4.70, P<0.01) tranilast significantly antagonized the decrease of the A values induced by TGF-β 2 in the cultured human trabecular meshwork cells. In comparison with the control group [817.37±124.21 cpm/104 cells], 12.5 μg/ml (620.33±80.46 cpm/104 cells, q'= 4.26, P< 0.05), 25 μg/ml (594.58±88.13 cpm/104 cells, q'=4.81, P<0.01), 50 μg/ml (418.64±67.90 cpm/104 cells, q'=8.62, P<0.01) tranilast significantly inhibited the incorporation of 3H-proline into the cultured human trabecular meshwork cells promoted by TGF-β 2 in a dose-dependent manner. It was concluded that tranilast had the antagonistic effect on the proliferation inhibition and collagen synthesis promotion induced by TGF-β 2 in the cultured human trabecular meshwork cells.

Effect of Transforming Growth Factor-β_2 on Phagocytosis in Cultured Bovine Trabecular Meshwork Cells

The effect of transforming growth factor β 2 (TGF β 2) on phagocytosis in bovine trabecular meshwork cells in vitro was investigated. After the cultured bovine trabecular meshwork cells were treated with 0 ng/ml, 0.32 ng/ml, 1 ng/ml, 3.2 ng/ml TGF β 2 for 24 h, latex beads were added into the incubation medium, and the numbers of the latex beads in 20 adjacent cells were counted under a microscope 24 h later, after treatment with Wright's stain. Our results showed that the average numbers of the latex beads in the trabecular meshwork cells treated with TGF β 2 of different concentrations were 53.1±1.7 beads/cell, 56.4±2.9 beads/cell and 77.9±6.5 beads/cell respectinvely, in comparison with 45.5±3.3 beads/cell of the control group. TGF β 2 significantly increased the number of the latex beads phagocytosed by cultured bovine trabecular meshwork cells in a dose dependent manner. TGF β 2 could promote the phagocytosis of bovine trabecular meshwork cells in vitro . It may be involved in the cellularity decrease of the trabecular meshwork in the patients of primary open angle glaucoma through promoting the phagocytosis of trabecular meshwork cells.

Alcohol Dehydrogenase Activity in Cultured Cells from Different Tobacco (Nicotiana tabacum L.) Varieties

The activity of alcohol dehydrogenase (ADH) in cultured cells of various tobacco was determined. It was found that significant differences existed in cells of different varieties cultured under normal conditions and as well after treated with exogenous ethanol. The ADH activity had positive relation with the ability of the cells to catabolize exogenous ethanol, indicating that the main function of the ADH in tobacco cells was in the direction of converting ethanol to acetaldehyde.

The inhibitory effect of calcitonin gene-related peptide on adriamycin induced acute cardiotoxicity in cultured myocardial cells

Objective: To observe the inhibitory effect of calcitonin gene--related peptide (CGRP) on adriamycininduced acute cardiotoxicity. Methods: Primarily cultured rat myocardial cells were treated with 10-6 mol/Ladriamycin and 10-6mol/L adriamycin + 10 8mol/I. CGRP. Lactate dehydrogenase (LDH ) activity in the mediumand the contents of malondialdehyde (MDA ). calcium. and magnesium in the myocardial cells were assayed.Results: In the adriamycin group, LDH activity in medium and calcium, MDA contents in myocardial cells weresignificantly increased compared with those in control group, and magnesium content in the myocardial cells wassignificantly reduced. In the adriamycin group. there was a positive correlation between LDH activity in themedium and MDA content in the myocardial cells. Meanwhile, in the adriamycin + CGRP group,- CGRP mightsignificantly reduce the leakage of LDH from myocardial cells, lessen the increase in calcium and MDA contentsand prevent the loss of magnesium. Conclusion: CGRP may inhibit adriamycin induced acute cardiotoxicity byinhibiting lipid peroxidation, attenuating calcium overload, magnesium loss, and protecting enzyme activity.

Immunocytochemical characteristics of cultured human retinal pigment epithelial cells

Objective: To investigate the immunocytochemical characteristics of cultured human retinal pigment epithelial cells (RPEC). Methods: Indirect immunofluorescence mehtods were applied to study the expression of keratin, vimentin, actin, Ⅷ factor and glial fibrillary acidic protein (GFAP), and HAM45 in the 1st-passage and the 3rd- to 6th-passages of RPEC. Results: subcultured human RPEC demonstrated positive staining for keratin and vimentin protein; keratin reactivity was a constant feature of all human RPEC.The first-passage RPEC did not stain with abtibodies to vimentin, or stained very weakly. After passaged for 3 to 6 times, however, RPEC demonstrated intensively positive staining for vimentin. BPEC expressed generally negative staining for actin, Ⅷ factor, GFAP,and HAM45. Conclusion: Cultured RPECs always express keratin other than proteins of actin, Ⅷ factor, GFAP and HAM45. Protein vimentin expression intensity of RPEC increases with more passages. This indicates alternative phenotype of RPEC due to cell cultural conditions.

EFFECT OF RADIX SALVIAE MILTIORRHIZAE ON GROWTH OF ISOLATED CELLS FROM EMBRYONIC CHICKEN FRONTAL BONE CULTURED IN VITRO (A HISTOCHEMICAL STUDY) Ⅱ.THE DEVELOPMENT AND MATURATION OF OSTEOBLAST-LIKE CELLS

The isolated osteoblast-like cells from embryonic chicken frontal bone werecultured in vitro and histochemical methods adopted to observe the effect of RadixSalviac Miltiorrhizae (RSM) on proliferation, differentiation, and osteogenic capacity ofthese cells. It was found that: 1. The mitosis and proliferation of the osteoblast-like cellscould be accelerated by RSM, resulting in increased density of the cells in RSM groupas compared with the control. 2. After 48 h, the pseudopodia stretched out and drew backactively in osteoblast-like cells in RSM group. Small particles produced in the cells weresecreted through exocytosis to the extracellular medium. However, in the control group,the capacity to form and secrete these particles was limited. These particles showed posi-tive Alcian blue staining in Alcian blue-Sirius red reaction, so they were acidmucopolysaccharide particles. 3. The osteoblast-like cells could secrete vesicular particles 3micra in diameter. These vesicular particles could be stained with Alcian blue in earlystage, then they could be stained with Sirius red, and finally by Alizarin red S. Thesevesicular particles could aggregate and fuse around the cell colonies, forming bonenodules and bone flakes. The quantity and volume of the bone nodules and flakes inRSM group were larger than in the control group. 4. The bone nodules and flakes couldbe labeled vitally with tetracycline, and show strong yellow fluorescence under thefluorescence microscope. Therefore, these substances were the newly formed bone sub-stances.