Objective To investigate the effects of removing microglia from spinal cord on nerve repair and functional recovery after spinal cord injury (SCI) in mice. MethodsThirty-nine 6-week-old female C57BL/6 mice were randomly divided into control group (n=12), SCI group (n=12), and PLX3397+SCI group (n=15). The PLX3397+SCI group received continuous feeding of PLX3397, a colony-stimulating factor 1 receptor inhibitor, while the other two groups were fed a standard diet. After 14 days, both the SCI group and the PLX3397+SCI group were tested for ionized calcium binding adapter molecule 1 (Iba1) to confirm that the PLX3397+SCI group had completely depleted the spinal cord microglia. The SCI model was then prepared by clamping the spinal cord in both the SCI group and the PLX3397+SCI group, while the control group underwent laminectomy. Preoperatively and at 1, 3, 7, 14, 21, and 28 days postoperatively, the Basso Mouse Scale (BMS) was used to assess the hind limb function of mice in each group. At 28 days, a footprint test was conducted to observe the gait of the mice. After SCI, spinal cord tissue from the injury site was taken, and Iba1 immunofluorescence staining was performed at 7 days to observe the aggregation and proliferation of microglia in the spinal cord. HE staining was used to observe the formation of glial scars at the injury site at 28 days; glial fibrillary acidic protein (GFAP) immunofluorescence staining was applied to astrocytes to assess the extent of the injured area; neuronal nuclei antigen (NeuN) immunofluorescence staining was used to evaluate neuronal survival. And 5-hydroxytryptamine (5-HT) immunofluorescence staining was performed to assess axonal survival at 60 days. Results All mice survived until the end of the experiment. Immunofluorescence staining revealed that the microglia in the spinal cord of the PLX3397+SCI group decreased by more than 95% compared to the control group after 14 days of continuous feeding with PLX3397 (P<0.05). Compared to the control group, the BMS scores in the PLX3397+SCI group and the SCI group significantly decreased at different time points after SCI (P<0.05). Moreover, the PLX3397+SCI group showed a further decrease in BMS scores compared to the SCI group, and exhibited a dragging gait. The differences between the two groups were significant at 14, 21, and 28 days (P<0.05). HE staining at 28 days revealed that the SCI group had formed a well-defined and dense gliotic scar, while the PLX3397+SCI group also developed a gliotic scar, but with a more blurred and loose boundary. Immunofluorescence staining revealed that the number of microglia near the injury center at 7 days increased in the SCI group than in the control group, but the difference between groups was not significant (P>0.05). In contrast, the PLX3397+SCI group showed a significant reduction in microglia compared to both the control and SCI groups (P<0.05). At 28 days after SCI, the area of spinal cord injury in the PLX3397+SCI group was significantly larger than that in SCI group (P<0.05); the surviving neurons significantly reduced compared with the control group and SCI group (P<0.05). The axonal necrosis and retraction at 60 days after SCI were more obvious. ConclusionThe removal of microglia in the spinal cord aggravate the tissue damage after SCI and affecte the recovery of motor function in mice, suggesting that microglia played a neuroprotective role in SCI.
In this study, the role of newcastle disease virus (NDV) combined thermic solidified tumor vaccine in inhibiting growth of tumor and immune control was investigated, and rate of inhibiting tumor and cellular immunity were measured. The results showed that rate of inhibiting tumor in experimental group Ⅰ and Ⅱ were 24.8% and 41.1% respectively; average weight of tumor was significantly lower in both experimental groups than in control group, and activity of natural killing (NK) cells in experimental groups was higher than that in control group (Ｐ＜0.01). This suggests that NDV combined thermic solidified tumor vaccine can inhibit growth of tumor and improve activity of NK cells, and their effects are better than that of NDV.
The model of transplanted colonic SW480 cell line carcinoma in gymnomouse body was set up to observe the effect of octapeptide somatostatin (SMS 201-995,SMS) on the transplanted carcinoma and elucidate its mechanism. Results: the volume, weight, DNA and protein content in carcinoma cell, cell amount and proliferation index of S and G2M phase in SMS group and SMS+PG (pentagastrin) group were markedly lower than those in PG group and control group, those of PG group were markedly higher than those in control group.The cell amount of G0/G1 phase in SMS group and SMS+PG group was markedly higher than that in PG group and control group, and that of PG group was markedly lower than that in control group.All these suggested that somatostatin could not only inhibit the growth of transplanted human colonic SW480 cell line carcinoma directly but also inhibit the growthpromoting effect of gastrin on the transplanted carcinoma.The mechanism might be that somatostatin inhibit the synthesis of cAMP, DNA and protein in carcinoma cells, then inhibit the cell growing from G0/G1 phase to S and G2M phases.Our study might provide experimental basis for the homonotherapy with analogue of somatostatin in patients with large intestine carcinoma.
ObjectiveBased on the cell-extracellular matrix adhesion theory in selective cell retention (SCR) technology, demineralized bone matrix (DBM) modified by simplified polypeptide surface was designed to promote both bone regeneration and angiogenesis.MethodsFunctional peptide of α4 chains of laminin protein (LNα4), cyclic RGDfK (cRGD), and collagen-binding domain (CBD) peptides were selected. CBD-LNα4-cRGD peptide was synthesized in solid phase and modified on DBM to construct DBM/CBD-LNα4-cRGD scaffold (DBM/LN). Firstly, scanning electron microscope and laser scanning confocal microscope were used to examine the characteristics and stability of the modified scaffold. Then, the adhesion, proliferation, and tube formation properties of CBD-LNα4-cRGD peptide on endothelial progenitor cells (EPCs) were detected, respectively. Western blot method was used to verify the molecular mechanism affecting EPCs. Finally, 24 10-week-old male C57 mice were used to establish a 2-mm-length defect of femoral bone model. DBM/LN and DBM scaffolds after SCR treatment were used to repair bone defects in DBM/LN group (n=12) and DBM group (n=12), respectively. At 8 weeks after operation, the angiogenesis and bone regeneration ability of DBM/LN scaffolds were evaluated by X-ray film, Micro-CT, angiography, histology, and immunofluorescence staining [CD31, endomucin (Emcn), Ki67].ResultsMaterial related tests showed that the surface of DBM/LN scaffold was rougher than DBM scaffold, but the pore diameter did not change significantly (t=0.218, P=0.835). After SCR treatment, DBM/LN scaffold was still stable and effective. Compared with DBM scaffold, DBM/LN scaffold could adhere to more EPCs after the surface modification of CBD-LNα4-cRGD (P<0.05), and the proliferation rate and tube formation ability increased. Western blot analysis showed that the relative expressions of VEGF, phosphorylated FAK (p-FAK), and phosphorylated ERK1/2 (p-ERK1/2) proteins were higher in DBM/LN than in DBM (P<0.05). In the femoral bone defect model of mice, it was found that mice implanted with DBM/LN scaffold had stronger angiogenesis and bone regeneration capacity (P<0.05), and the number of CD31hiEmcnhi cells increased significantly (P<0.05).ConclusionDBM/LN scaffold can promote the adhesion of EPCs. Importantly, it can significantly promote the generation of H-type vessels and realize the effective coupling between angiogenesis and bone regeneration in bone defect repair.
Objective To explore heterotopic chondrogenesis of canine myoblasts induced by cartilage-derived morphogenetic protein 2 (CDMP-2) and transforming growth factor β1 (TGF-β1) which were seeded on poly (lactide-co-glycolide) (PLGA) scaffolds after implantation in a subcutaneous pocket of nude mice. Methods Myoblasts from rectus femoris of 1-year-old Beagle were seeded on PLGA scaffolds and cultured in medium containing CDMP-2 and TGF-β1 for 2 weeks in vitro. Then induced myoblasts-PLGA scaffold, uninduced myoblasts-PLGA scaffold, CDMP-2 and TGF-β1-PLGA scaffold, and simple PLGA scaffold were implanted into 4 zygomorphic back subcutaneous pockets of 24 nude mice in groups A, B, C, and D, respectively. At 8 and 12 weeks, the samples were harvested for general observation, HE staining and toluidine blue staining, immunohistochemical staining for collagen type I and collagen type II; the mRNA expressions of collagen type I, collagen type II, Aggrecan, and Sox9 were determined by RT-PCR, the glycosaminoglycans (GAG) content by Alician blue staining, and the compressive elastic modulus by biomechanics. Results In group A, cartilaginoid tissue was milky white with smooth surface and slight elasticity at 8 weeks, and had similar appearance and elasticity to normal cartilage tissue at 12 weeks. In group B, few residual tissue remained at 8 weeks, and was completely degraded at 12 weeks. In groups C and D, the implants disappeared at 8 weeks. HE staining showed that mature cartilage lacuna formed of group A at 8 and 12 weeks; no cartilage lacuna formed in group B at 8 weeks. Toluidine blue staining confirmed that new cartilage cells were oval and arranged in line, with lacuna and blue-staining positive cytoplasm and extracellular matrix in group A at 8 and 12 weeks; no blue metachromatic extracellular matrix was seen in group B at 8 weeks. Collagen type I and collagen type II expressed positively in group A, did not expressed in group B by immunohistochemical staining. At 8 weeks, the mRNA expressions of collagen type I, collagen type II, Aggrecan, and Sox9 were detected by RT-PCR in group A at 8 and 12 weeks, but negative results were shown in group B. The compressive elastic modulus and GAG content of group A were (90.79 ± 1.78) MPa and (10.20 ± 1.07) μg/mL respectively at 12 weeks, showing significant differences when compared with normal meniscus (P lt; 0.05). Conclusion Induced myoblasts-PLGA scaffolds can stably express chondrogenic phenotype in a heterotopic model of cartilage transplantation and represent a suitable tool for tissue engineering of menisci.
ObjectiveTo summarize the common mouse models and the latest research progress in the basic research of colorectal cancer, introducing advantages, disadvantages and applications of these various models, provide references for the researchers in the selection of mouse models for their experiments.MethodRetrieved the related literatures from databases including PubMed, Web of Science, CNKI and WanFang, and after reading the literatures, different methods were sorted out, analyzed and summarized.ResultsThe mouse models commonly used in colorectal cancer research include the cell-derived xenograft (CDX), patient-derived xenograft (PDX), chemical reagent-induced tumor in situ, transgenic mice (ApcMin/+ mice), tumor cells derived from mice themselves were inoculated to the normal mice, and models of colorectal metastatic tumors (including liver, lung, abdomen and bone metastases, etc.). The CDX model cost shorter time to establish, and the PDX model restored the authentic phenotype of the tumor in patients, but the tumor were both colonized under the skin of nude mice, which lacked authenticity tumor microenvironment. The colorectal cancer in mice induced by chemical reagents and genetically engineered mice imitated the development of colorectal tumor in the situ intestine of mouse, but both of them were time-consuming. The model established by the tumor of mouse own was convenient for basic immune research of colorectal cancer, but the disadvantage was the unreal tumor microenvironment. The colorectal cancer metastasis model was an essential model for the study of the mechanism and treatment in metastasis colorectal tumor, but its establishment required higher operating skills and required the image examination to determine the whether the metastasis tumor was successfully generated or not.ConclusionsDifferent mouse models of colorectal cancer have different emphases, advantages and disadvantages. Researchers need to make accurate selection according to the research purpose and design needs.
Mouse animal models are the most commonly used experimental tools in scientific research, which have been widely favored by researchers. The animal model of mouse leukemia appeared in the 1930s. During the past 90 years, researchers have developed various types of mouse leukemia models to simulate the development and treatment of human leukemia in order to promote effectively the elucidation of the molecular mechanism of leukemia' development and progression, as well as the development of targeted drugs for the treatment of leukemia. Considering that to myeloid leukemia, especially acute myeloid leukemia, there currently is no good clinical treatment, it is urgent to clarify its new molecular mechanism and develop new therapeutic targets. This review focuses on the various types of mouse models about myeloid leukemia used commonly in recent years, including mouse strains, myeloid leukemia cell types, and modeling methods, which are expected to provide a reference for relevant researchers to select animal models during myeloid leukemia research.
In the development of radio frequency (RF) coils for better quality of the mini-type permanent magnetic resonance imager for using in the small animal imaging, the solenoid RF coil has a special advantage for permanent magnetic system based on analyses of various types of RF coils. However, it is not satisfied for imaging if the RF coils are directly used. By theoretical analyses of the magnetic field properties produced from the solenoid coil, the research direction was determined by careful studies to raise further the uniformity of the magnetic field coil, receiving coil sensitivity for signals and signal-to-noise ratio (SNR). The method had certain advantages and avoided some shortcomings of the other different coil types, such as, birdcage coil, saddle shaped coil and phased array coil by using the alloy materials (from our own patent). The RF coils were designed, developed and made for keeled applicable to permanent magnet-type magnetic resonance imager, multi-coil combination-type, single-channel overall RF receiving coil, and applied for a patent. Mounted on three instruments (25 mm aperture, with main magnetic field strength of 0.5 T or 1.5 T, and 50 mm aperture, with main magnetic field strength of 0.48 T), we performed experiments with mice, rats, and nude mice bearing tumors. The experimental results indicated that the RF receiving coil was fully applicable to the permanent magnet-type imaging system.
Objective To study the culture and purification of the fetal mouse liver mesenchymal stem cells(MSCs) in vitro and to investigate their differentiation potential and the composite ability with true bone ceramic(TBC). Methods The single cell suspension of MSCs was primarily cultured and passaged, which was prepared from the fetal mouse liver; the flow cytometry was applied to detectCD29, CD34, CD44 and CD45. The osteogenic differentiation was induced in chemical inducing system; the osteogenic induction potency was tested. The purified fetal mouse liver MSCs were compounded with TBC covered with collagen type Ⅰ in vitro and the cell attachment and proliferation to the TBC were observed. Results The primary MSCs of fetal mouse liver were easy to culture in vitro. They proliferated well and were easy to subcultured. The proliferation ability of primary and passaged MSCs was similar. Flow cytometric analysis showed the positive results for CD29, CD44 and the negative results for CD34, CD45. After 7 days of induction, the MSCs expressed collagen type I and alkaline phosphatase(ALP) highly. After 14 days of induction, the fixed quantity of ALP increased significantly. After 28 days of induction, calcium accumulation was observed by Von Kossa’s staining. Many liver MSCs attached to the surface of TBC. Conclusion The MSCs of the fetalmouse liver can be obtained, subcultured and purified easily. After culturing in chemical inducing system, the MSCs of fetal mouse liver can be successfully induced to osteoblast-like cells, attach to the surface of TBC and proliferate well.
Objective To provide experimental evidence for the clinical application of ischemia therapy to treating pancreatic cancer. Methods After the model of pancreatic transplanted cancer was established in nude mice with orthotransplantation of human pancreatic cancer cell line into the pancreas, the ischemia of the right lobe of the pancreas was induced with ligation of the gastroduodenal, inferior pancreaticoduodenal and dorsal pancreatic arteries. Effects of regional ischemia on the growth of transplanted cancer and the pathomorphology of the transplanted cancer and pericancerous tissue were investigated. Results The transplanted cancer grew slower and its doubling time was longer in the ischemic group than in the control. On the 3rd, 7th and 14th day after operation, the size of transplanted cancer, the proliferative index and protein content of the cancer cells were significantly lower in the ischemic group than in the control (Ｐ＜0.01). Optical microscopy revealed large areas of coagulation necrosis, necrobiotic cells and the infiltration of inflammatory cells. The atrophy of acini, fibrosis and the infiltration of lymphocyte cells were found in pericancerous tissue. Conclusion Regional ischemia can destroy and inhibit the pancreatic transplanted cancer in nude mice effectively. The ischemia changes of pericancerous tissue may be unfavourable for the growth of the pancreatic transplanted cancer.