BACKGROUND:Rat models of diabetes mellitus type 2 (T2DM) are usually induced by the combination of high-fat diet and low-dose streptozotocin, but their effects on the intervertebral disc have not yet been reported. Endplate sclerosis is an important factor contributing to intervertebral disc degeneration. OBJECTIVE:To evaluate whether the rat T2DM model induced by high-fat diet combined with low-dose streptozotocin is suitable for the study of T2DM related intervertebral disc degeneration. METHODS:Thirty-two 3-month-old female Sprague-Dawley rats were divided into four groups (n=8 per group), including sham, bilateral variectomy, DM, and bilateral variectomy plus DM groups, followed by subjected to bilateral ovariectomy and/or high-fat diet combined with low-dose streptozotocin, respectively. The blood glucose level, body mass and glucose tolerance were determined. The bone mineral density of the lumbar spine was measured after 8-week streptozotocin treatment. The L5-6 segments were removed and cut through midst sagittal plane after decalcification, and then underwent Von Gieson staining and histological degeneration scoring, and the disc height and endplate thickness were measured. RESULTS AND CONCLUSION:Fasting blood glucose and random blood glucose levels in the DM and bilateral variectomy plus DM groups were significantly higher than those in the other two groups, and the insulin sensitivity in the DM and bilateral variectomy plus DM groups were significantly lower than that in the other groups (P<0.05). L4-6 vertebral bone mineral density in the bilateral variectomy group was significantly lower than that in the sham group (P<0.05);L5-6 vertebral bone mineral density in the DM and bilateral variectomy plus DM groups was significantly lower than that in the sham group (P<0.05). L5-6 vertebral histological scores in the DM and bilateral variectomy plus DM groups were significantly higher than those in the other groups (P<0.05). Similar with the bilateral variectomy group, there were chondrometaplasia and mucoid degeneration of nucleus pulposus cells in the bilateral variectomy plus DM group, and the histological scores were significantly higher than those in the sham and DM groups (P<0.05). Compared with the sham group, the intervertebral disc height in the bilateral variectomy and bilateral variectomy plus DM groups was significantly decreased (P<0.05). While, there was no significant difference in the endplate thickness among groups. These results indicate the combination of high-fat diet and low-dose streptozotocin-induced rat T2DM models possess diabetic characteristics, but the rat intervertebral disc tissues show no significant differences from the normal ones;therefore, this model may be unsuitable for the study on T2DM-related intervertebral disc degeneration.

Objective:To analyze the molecular epidemiological characteristics of the Corona virus disease 2019 (COVID-19) cases in Shijiazhuang, which can reveal the origin of the outbreak and provide a scientific basis for COVID-19 prevention and control.Methods:From January 2 to January 8, 2021, a total of 404 samples from 170 COVID-19 cases were collected from the Shijiazhuang Fifth Hospital. The consensus sequence of 2019 novel Coronavirus(2019-nCoV) was obtained through multiplex polymerase chain reaction-based sequencing. The sequences of 170 COVID-19 cases were analyzed by the PANGOLIN, and the data were statistically analyzed by T-test.Results:Among the 404 COVID-19 samples, a total of 356 samples obtained high quality genome sequences (>95%,100×sequencing depth). The whole genome sequences of 170 COVID-19 cases were obtained by eliminating repeated samples. All 170 sequences were recognized as lineage B1.1 using PANGOLIN. The number of single nucleotide polymorphism arrange from 18-22 and most of the single nucleotide polymorphism were synonymous variants. All of 170 genomes could be classified into 48 sub-groups and most of the genomes were classified into 2 sub-groups (66 and 31, respectively).Conclusions:All cases in this study are likely originated from one imported case. The viruses have spread in the community for a long time and have mutated during the community transmission.