Objective: To constructCSF1R+/-mice and to analyze their genotypes, so as to provide animal model basis for disease pathological mechanism and drug target. Methods : A linearized targeting vector was designed according to Cre/Loxp system. A Loxp site was inserted upstream of the 5th exon of theCSF1Rgene, and a neomycin resistance box with Loxp sites on both sides was inserted downstream of the 5th exon. The linearized targeting vector was electroporated into embryonic stem cells. The correctly targeted embryonic stem cells were injected into the blastocysts of C57BL/6J mice to obtain chimeric mice, which were bred with Zp3-Cre mice. The newborn mice were numbered 9-14 days after birth and their tails were cut. The DNA of the mice was extracted, and the genotype of the mice was identified by polymerase chain reaction and agarose gel electrophoresis. The expression of CSF1R in mouse macrophages was detected by flow cytometry. The expression of CSF1R in mouse tissues was detected by Western blot. Results: The results of agarose gel electrophoresis showed that 453 bp bands were amplified in wild type mice, and 453 bp and 650 bp bands were amplified in heterozygous mice. The results of flow cytometry showed that the expression of CSF1R in peritoneal macrophages and bone marrow-derived macrophages of CSF1R heterozygous mice was lower than that of WT group(P<0.05). The results of Western blot showed that the expression of CSF1R in spleen, kidney and brain tissue of CSF1R heterozygous group was lower than that of WT group(P<0.05). Conclusion CSF1R+/-mice are successfully constructed, reproduced and identified, which provides an animal model basis for further revealing the potential mechanism of CSF1R in immune regulation.

Objective : To construct a humanized mouse model of the interleukin-9 receptor(IL-9R) coding DNA sequence(CDS) gene and to verify the genotype and IL-9R expression in mice. Methods : The CRISPR/Cas9 genome editing technology was used to replace the exon 2-7 fragment of the il-9r gene in mouse embryonic stem cells with the corresponding human IL-9R sequence. After verifying the completion of the gene fragment replacement, tetraploid embryos were constructed and microinjected back into the oviducts of surrogate mice. Through surrogacy by female mice, homozygous humanized mice were obtained. DNA was extracted from the homozygous humanized mice IL-9R CDS gene, and their genotypes were identified by agarose gel electrophoresis after PCR amplification. Western blot was used to detect the expression of IL-9R in the spleen and thymus of homozygous humanized mice with either wild-type(WT) or IL-9R gene humanization. Results : Gel electrophoresis after PCR amplification showed that mice with only a 1 805 bp band amplified using WT primers were wild-type, while mice with 2 553 bp and 2 340 bp bands amplified using 5KI and 3KI primers, respectively, were homozygous humanized mice with IL-9R CDS gene. Western blot results indicated that the tissues of homozygous humanized mice model with IL-9R CDS gene expressed IL-9R significantly. Conclusion The humanized mouse model with IL-9R CDS gene has been successfully constructed and characterized.

Objective: To construct microRNA(miR)-22 gene knockout(miR-22-/-) mice using CRISPR/Cas 9 technology, to breed miR-22-/- mice and to identify their genotypes. Methods : In this experiment, CRISPR/Cas 9 technology was used to construct miR-22-/- genetically engineered mice. After gene identification, the F0 generation miR-22-/- mice were mated with wild-type mice in the same litter to obtain F1 generation miR-22-/- mice. The miR-22 knockout efficiency was analyzed at the RNA level by real-time fluorescence quantitative polymerase chain reaction(qPCR). Western blot was used to detect the interaction between miR-22 and target genes. Results : miR-22-/- mice were successfully constructed using CRISPR/Cas 9 technology, gene identification was performed on the bred mice, and three stable genotypes of miR-22+/+,miR-22+/-, and miR-22-/- were identified. The real-time fluorescence quantitative PCR detection results confirmed that miR-22-/- mice showed almost no expression of miR-22 in the heart, liver, lung, kidney, spleen, and thymus tissues compared to wild-type mice in the same litter. Western blot analysis showed that the relative expression level of NLRP3 protein in miR-22-/- mouse tissues was lower than that in wild-type mice. Conclusion A miR-22-/- mouse model is successfully constructed, and stable genetic homozygous miR-22-/- mice is obtained. This indicates that miR-22 has an inhibitory effect on the downstream target gene NLRP3.

Objective: To explore the breeding and genotyping of CCR2 knockout mice, and to verify the applicability of the polymerase chain reaction(PCR) method for genotype detection of CCR2 knockout mice. Methods: The introduced CCR2 pure male mice and wild-type female mice were mated and bred to produce the offspring generation, the obtained F1 generation heterozygous mice were continued to be mated. DNA was extracted by clipping the tail tissues of the mice at the age of 2 weeks, the target gene fragment was amplified by PCR, and the genotypic results were determined by agarose gel electrophoresis. The proportion of purebred progeny carrying the CCR2 knockout gene was increased by genetic crosses, the effect of CCR2 knockout in the progeny mice was verified by using Western blot against major immune cells and key organs, and flow cytometry was used to detect whether the knockout of the CCR2 gene had any effect on the function of the immune system by targeting the major immune cells. Results: CCR2 knockout mice were successfully bred and characterized, and three genotypes of F2 generation mice were obtained: CCR2+/+, CCR2+/-, and CCR2-/-. The offspring genotypes were identified by PCR, and Western blot showed extremely low CCR2 protein expression in CCR2 knockout mice. Flow analysis showed that CCR2 knockdown reduced the expression of CD4+T and Th1 cells in mouse spleen-derived T cells, but did not affect macrophage function. Conclusion Correct breeding and identification are important ways to get the pure CCR2 knockout mice, and PCR method for identifying mouse genotypes is simple, fast and reliable.

Objective To construct myeloid-specific Spi1 gene knockout mice and analyze their genotypes,so as to provide animal model basis for the study of pathological mechanism of diseases and drug targets.Methods Ac-cording to the principle of CRISPR/Cas9 technology and Cre/LoxP system,sgRNA and Donor vectors were de-signed and constructed.The transcript of Exon 2(Exon 2)was used as the knockout region,and Loxp elements were placed on both sides of Exon 2.Cas9 protein,sgRNA and Donor vector were mixed and microinjected into the fertilized eggs of C57BL/6J mice,the fertilized eggs were transplanted into the uterus of C57BL/6J pregnant female mice,and F0 generation was obtained after 19～20 days.Positive F0 mice were mated with C57BL/6J mice to ob-tain stable F1 Spi1flox/+mice.Spi1flox/+mice of F1 generation were selfed to obtain Spi1flox/flox mice.Spi1flox/flox mated with Lyz2-Cre+mice to obtain Spi1flox/+/Lyz2-Cre+mice,and then mated with Spi1flox/flox,the Spi1flox/flox/Lyz2-Cre+mice were myeloid-specific Spi1 gene knockout(KO)mice.Spi1flox/flox/Lyz2-cre-mice were used as wild-type(WT)mice.DNA of WT and KO mice was extracted,and the genotypes were identified by agarose gel electro-phoresis after PCR amplification.Western blot was used to detect the expression of spleen focus forming virus provi-ral integration oncogene,Spi-1/purine rich box-1(PU.1)in immune cells of WT and KO mice.Results The results of PCR identification showed that the genotype of mice with only 220 bp amplified by flox primer was Spi1flox/flox homozygote,and the genotype of mice with 700 bp amplified by Lyz2-Cre primer was Lyz2-Cre+.Western blot showed that compared with WT group,the protein PU.1 was not expressed in bone marrow-derived macropha-ges(BMDMs)and peritoneal macrophages(PM)in KO group(P<0.01).There was no significant difference of statistics in the expression level of PU.1 in T cells between KO mice and WT mice.The results of PCR and West-ern blot showed that myeloid-specific Spi1 KO mice were successfully constructed.Conclusion The myeloid-spe-cific Spi1 gene KO mice are successfully constructed and identified,which provides animal model basis for further revealing the potential mechanism of PU.1 inimmune regulation.

Objective To breed and identify the T lymphocyte-conditional Spi1 knockout mice for the further in-vestgation of the specific role of Spi1-encoded protein PU.1.Methods The Lck-Cre mice were mated with Spi1flox/flox mice to obtain Lck-Cre×Spi1flox/flox mice(T lymphocyte-specific Spi1 knockout mice),and the genotype was determined by polymerase chain reaction(PCR)and agarose gel electrophoresis.Magnetic beads were used to sort out the splenic T lymphocytes,and the knockdown efficiency of PU.1 in T cells was detected by Western blot,quantitative real-time PCR(qPCR)and flow cytometry.Results The Lck-Cre×Spi1flox/flox mouse genotype was stably inherited.Compared with Spi1flox/flox mice,the expression level of PU.1 was significantly reduced in splenic T cells of Lck-Cre×Spi1flox/flox mice.Conclusion In this study,the T lymphocyte-specific Spi1 knockout mice was successfully constructed by applying Cre/LoxP system and CRISPR/Cas9 technology,which provided a reliable an-imal model for the subsequent experiments of the specific role of PU.1 in T cell-related diseases.

Objective To construct Csf1r-CreERT2 R26REYFP reporter gene mice and assess the efficacy of Csf1r-CreERT2-mediated enhancement of CSF1R in CD45+cells labeled with yellow fluorescein protein EYFP.Methods Csf1r-CreERT2 mice were crossbred with R26REYFP homozygous mice,and Csf1r-CreERT2R26REYFP mice were identified through PCR and Western Blot analyses.Flow cytometry was employed to evaluate CSF1R tag-efficiency in CD45+cells across different mouse tissues following tamoxifen induction.Results Csf1r-CreERT2 R26REYFP reporter gene mice were acquired.In addition,it was found that Csf1r-CreERT2-mediated EYFP could effectively mark CSF1R in various tissues of mice and CD45+cells in different locations.Compared to the R26REYF P group,the highest labeling efficiency was observed in the brain tissue(P＜0.001),the lowest in the thymus tissue(P＜0.05),and no sig-nificant difference was observed in the spleen tissue.Conclusion Adult Csf1r-CreERT2 mice and R26REYFP mice are effective ways to obtain Csf1r-CreERT2 R26REYFP induced conditional fluorescence mice.Csf1r-CreERT2 can mediate EYFP to effectively trace CSF1R in CD45+cells in different parts of mice.

Objective To investigate the expression of Acyl-CoA synthetase long-chain family member 4(ACSL4)in liver cancer and its role in regulating ferroptosis and proliferation of liver cancer cells.Methods Clinical samples of liver cancer and adjacent normal liver tissues were examined for malondialdehyde(MDA)contents and for expressions of mRNA and protein expressions of ACSL4 and proliferating cell nuclear antigen(PCNA)using RT-qPCR and Western blotting.Human liver cancer Huh-7 cells were treated with Erastin(a ferroptosis inducer),Fer-1(a ferroptosis inhibitor),or both,and the changes in expression levels of MDA,ACSL4 and PCNA were detected,and the cell proliferation was assessed with plate cloning assay.Results MDA contents were lower and ACSL4 and PCNA expressions were higher significantly in liver cancer tissues than in adjacent liver tissues.In Huh-7 cells,Erastin treatment significantly inhibited mRNA and protein expressions of ACSL4 and PCNA,suppressed cell proliferation,and increased MDA contents.Fer-1 alone did not produce significant effect on cell viability but reversed the effect of Erastin on ACSL4 and PCNA expressions,cell proliferation and MDA contents.Conclusion ACSL4 level is significantly overexpressed in liver cancer.Erastin increases MDA contents and down-regulates ACSL4 expression,thereby promoting ferroptosis and inhibiting proliferation of liver cancer cells,and these effects can be reversed by Fer-1.

Surgery is the important treatment for each type of thyroid cancer. Single or multiple parathyroid injuries or blood supply disorders may occur during the operation, resulting in dramatic decline of parathyroid hormone and hypocalcemia after operation, which is common in clinical practice. After discharge, chronic hypocalcemia can cause great physical and psychological pain to patients. Although the residual parathyroid glands can compensate after surgery in some cases, long-term negative calcium balance and postoperative hypocalcemia may cause excessive hyperplasia of the residual parathyroid glands, resulting in parathyroid hyperfunction or even hyperparathyroidism, which can lead to osteoporosis, urinary calculi, metastatic vascular calcification, and systemic abnormal migratory calcium deposits. It’s advisable to enhance the awareness of the cause and harm of the postoperative hypocalcemia, evaluate and diagnose it early, and actively intervene in every stage of before, during and after the operation and long-term follow-up, which can effectively reduce the occurrence and severity of hypocalcemia and improve the postoperative life quality and the prognosis.

Thyroid cancer is the common malignant tumor in the neck, and surgery is the important treatment measure for it. Some patients suffer from hypoparathyroidism and hypocalcemia after thyroidectomy, which will seriously affect the patient’s life quality and prognosis. This article reported a case of 42 years old female patient with hypocalcemia for 6 years after total thyroidectomy due to thyroid cancer, who still had frequent hypocalcemia with high dose of oral calcium and active vitamin D supplementation. Long-term and frequent facial and limb numbness, convulsions, epileptic-like seizures and sudden unconsciousness afflicted her due to hypocalcemia. After admission, her symptoms were obviously relieved after one week of adequate calcium supplementation through oral administration or intravenous infusion under close monitoring. Upon discharge she was able to maintain the normal level of blood calcium by decreased dose of oral calcium supplementation alone. Long-term limb numbness, convulsions, low back pain, shoulder pain, walking instability and other symptoms disappeared basically. The epileptic-like seizures did not recur. During six months of follow-up, her blood calcium was still well controlled in normal level.