OBJECTIVES: Wild-caught Microtus fortis (M. fortis) at the age of 9-15 months can develop epithelial ovarian cancers similar to human epithelial ovarian cancers under natural conditions during experimental animal breeding, but its pathological types and biological characteristics remain unclear. This study aims to analyze the biological characteristics of spontaneous ovarian cancer in M. fortis, intending to develop M. fortis as an animal model for human epithelial ovarian cancer. METHODS: The female M. fortis (9-15 months old) with spontaneous ovarian cancer were selected as the experimental group, and healthy M. fortis from the same litter were selected as the control group. The ovarian pathological changes of the two groups were observed by dissection. Blood routine and biochemical indicators were measured by biochemical analysis. Hematoxylin and eosin (HE) staining was performed to observe the pathological changes in the ovarian cancer tissue of M. fortis. Immunohistochemical staining was used to detect the protein expression of common ovarian cancer markers, and real-time RT-PCR was used to analyze the transcription levels of ovarian cancer-related genes. RESULTS: Spontaneous ovarian cancer in M. fortis mainly affects both ovaries, with tumors appearing solid or cystic. HE staining and histopathological analysis confirmed that the ovarian tumors originated from ovarian surface epithelium. Compared to the control group, the experimental group showed significantly decreased hemoglobin (P<0.01), hematocrit (P<0.05), albumin (P<0.05), and blood glucose levels (P<0.01), while lymphocyte percentage (P<0.05), monocyte percentage (P<0.05), cholesterol (P<0.01), and progesterone (P<0.01) levels were significantly increased. Expression of ovarian cancer-related genes, including ID3, CDC42, RHOA, RB1CC1, NF1, PIN1, MIB1, PDS5A, MCM7, and MLH1, was significantly downregulated (all P<0.05), while PAX8 gene expression was significantly upregulated (P<0.05). Immunohistochemical results showed that Wilms' tumor gene 1 (WT1) protein was mainly distributed throughout the cell, with significantly higher expression in ovarian cancer M. fortis. Tumor protein 53 (TP53) was expressed in both healthy and ovarian cancer M. fortis and was distributed throughout the cell. Hepatocyte nuclear factor 1 beta (HNF1B) and progesterone receptor (PR) protein were highly expressed in the ovarian tissue of healthy M. fortis but were significantly reduced in the ovarian cancer M. fortis, though both were located in the cytoplasm. CONCLUSIONS Spontaneous ovarian cancer in M. fortis is serous ovarian cancer. Compared to healthy M. fortis, significant differences were observed in ovarian tissue morphology, biochemical indicators, ovarian cancer-related gene expression, and protein expression, which show similarity to the biological characteristics of human serous ovarian cancer. This suggests that M. fortis could be an ideal animal model for studying human serous ovarian cancer.
Female ; Ovarian Neoplasms/metabolism* ; Animals ; Carcinoma, Ovarian Epithelial ; Disease Models, Animal ; Humans ; Neoplasms, Glandular and Epithelial/metabolism* ; Ovary/pathology*

OBJECTIVES: Recent evidence suggests that the gut may be a primary site of metformin action. However, studies on the effects of metformin on gut microbiota remain limited, and its impact on gut microbial metabolites such as short-/medium-chain fatty acids is unclear. This study aims to investigate the effects of metformin on gut microbiota, short-/medium-chain fatty acids, and associated metabolic benefits in high-fat diet rats. METHODS: Twenty-four Sprague-Dawley rats were randomly divided into 3 groups: 1) Normal diet group (ND group), fed standard chow; 2) high-fat diet group (HFD group), fed a high-fat diet; 3) high-fat diet + metformin treatment group (HFD+Met group), fed a high-fat diet for 8 weeks, followed by daily intragastric administration of metformin solution (150 mg/kg body weight) starting in week 9. At the end of the experiment, all rats were sacrificed, and serum, liver, and colonic contents were collected for assessment of glucose and lipid metabolism, liver pathology, gut microbiota composition, and the concentrations of short-/medium-chain fatty acids. RESULTS: Metformin significantly improved HFD-induced glucose and lipid metabolic disorders and liver injury. Compared with the HFD group, the HFD+Met group showed reduced abundance of Blautia, Romboutsia, Bilophila, and Bacteroides, while Lactobacillus abundance significantly increased (all P<0.05). Colonic contents of butyric acid, 2-methyl butyric acid, valeric acid, octanoic acid, and lauric acid were significantly elevated (all P<0.05), whereas acetic acid, isoheptanoic acid, and nonanoic acid levels were significantly decreased (all P<0.05). Spearman correlation analysis revealed that Lactobacillus abundance was negatively correlated with body weight gain and insulin resistance, while butyrate and valerate levels were negatively correlated with insulin resistance and liver injury (all P<0.05). CONCLUSIONS Metformin significantly increases the abundance of beneficial bacteria such as Lactobacillus and promotes the production of short-/medium-chain fatty acids including butyric, valeric, and lauric acid in the colonic contents of HFD rats, suggesting that metformin may regulate host metabolism through modulation of the gut microbiota.
Animals ; Metformin/pharmacology* ; Rats, Sprague-Dawley ; Diet, High-Fat/adverse effects* ; Rats ; Gastrointestinal Microbiome/drug effects* ; Male ; Fatty Acids, Volatile/metabolism* ; Fatty Acids/metabolism*

Objective:Age-related cataract is the most common type of adult cataract and a leading cause of blindness.Currently,there are few reports on the establishment of animal models for age-related cataract.During the experimental breeding of Microtus fortis(M.fortis),we first observed that M.fortis aged 12 to 15 months could naturally develop cataracts.This study aims to explore the possibility of developing them as an animal model for age-related cataract via identifing and analyzing spontaneous cataract in M.fortis. Methods:The 12-month-old healthy M.fortis were served as a control group and 12-month-old cataractous M.fortis were served as an experimental group.The lens transparency was observed using the slit-lamp biomicroscope.Hematoxylin and eosin staining was used to detect pathological changes in the lens.Biochemical detection methods were applied to detect blood routine,blood glucose levels,the serum activities of superoxide dismutase(SOD),and glutathione peroxidase(GSH-Px)in both groups.Finally,real-time RT-PCR was used to detect the transcription levels of cataract-related genes in the lens of 2 groups. Results:Compared with the control group,the lens of cataract M.fortis showed severely visible opacity,the structure of lens was destroyed seriously,and some pathological damage,such as swelling,degeneration/necrosis,calcification,hyperplasia,and fiber liquefaction were found in lens epithelial cells(LECs).The fibrous structure was disorganized and irregularly distributed with morgagnian globules(MGs)aggregated in the degenerated lens fibers.There was no statistically significant difference in blood glucose levels between the experimental and control groups(P＞0.05).However,white blood cell(WBC)count(P＜0.05),lymphocyte count(P＜0.01),and lymphocyte ratio(P＜0.05)were significantly decreased,while neutrophil percentage(P＜0.05)and monocyte ratio(P＜0.01)were significantly increased.The serum activities of SOD and GSH-Px(both P＜0.05)were both reduced.The mRNAs of cataract-related genes,including CRYAA,CRYBA1,CRYBB3,Bsfp1,GJA3,CRYBA2,MIP,HspB1,DNase2B,and GJA8,were significantly downregultaed in the lenses of the experimental group(all P＜0.05). Conclusion:There are significant differences in lens pathological changes,peroxidase levels,and cataract-related gene expression between cataract and healthy M.fortis.The developed cataract spontaneously in M.fortis is closely related to age,the cataract M.fortis might be an ideal animal model for the research of age-related cataract.