AIM: To study urinary concentration of aquaporin-2 water channel protein(AQP2) at different stages of chronic heart failure(CHF) rats and its relation to hyponatremia. METHODS: Male Sprague-Dawley rats(200～250 g) underwent either a left coronary artery ligation (a model of CHF) or a sham-operation. At different stage after surgery, urinary AQP2 concentration was measured by Western blot. 24-hours urine volume, serum sodium and urine osmolality were measured at the same time. RESULTS: There were two peaks of urinary excretion of AQP2 in severe heart failure rats model: one was the third day after operation, the other was the 9th week. Serum sodium and urine osmolality were significantly different in CHF rats as compared with sham-operated rats. Seven weeks after surgery, urinary AQP2 concentration was increased significantly insevere CHF rats compared with the mild ones and the control ones(365%?103% vs 179%?81% and 99%?48%, P

AIM: To detect the change of urinary concentration of aquaporin-2 (AQP-2) by enzyme linked immunosorbent assay in rat models of different degrees of heart failure and make a comparison with sham-operation group.METHODS: This experiment was carried out between January 2000 and January 2002 in the animal laboratory of Nanfang Hospital of Southern Medical University. Forty-two male adult Sprague-Dawley rats were involved. Twenty-six rat models of chronic heart failure were prepared by ligation of left coronary artery. When left ventricle infarct area was≥20%, the rat models of congestive heart failure were successful (heart failure group, n =13); When left ventricle infarct area was＜20%, the rat models of congestive heart failure were unsuccessful (compensation group, n =13). The other 16 rats were not ligated at coronary rtery (control group). Serum sodium concentration was determined with BeckmanC×3 equipment and urine osmole by cryoscopic method. Urine volume of 24 hours was monitored. Urinary concentration ofAQP-2 level of rats was determined by double antibodies sandwich enzyme linked immunosorbent assay (DABs-ELISA).RESULTS: Forty-two rats were involved in the result analysis. The 24-hour urine volume and serum sodium concentration in the heart failure group and compensation group were significantly lower than those in the control group (P＜0.05-0.01), while urine osmole in two groups was significantly higher than that in the control group (P＜0.05-0.01).②At postoperative 4 and 6 weeks, urinary concentration of AQP-2 level of rats in the control group was significantly lower than that in the other two groups (P＜0.05-0.01), and urinary concentration of AQP-2 level of rats in the compensation group was significantly lower than that in the heart failure group (P＜0.05, 0.01).In the compensation group and heart failure group, urinary concentration of AQP-2 level of rats was significantly higher at postoperative 6 weeks than at postoperative 4weeks (P＜0.05).CONCLUSION:①AQP-2 is the key target protein of water retention and hyponatremia at heart failure.②Detection of urinary concentration of AQP-2 by ELISA can effectively reflect water retention and hyponatremia when heart failure occurs.

Objective To investigate the role and mechanism of SR8278,a synthetic antagonist of nuclear receptor subfamily 1 group D member 1(NR1D1),in alleviating the structural and functional impairment of the extraorbital lacrimal glands induced by jet lag in mice.Methods Totally 36 healthy wild C57BL/6J mice aged 8-10 weeks were randomly divid-ed into 3 groups(normal group,jet-lag group,and jet-lag+SR8278 group)after adapting to a circadian rhythm chamber under the 12 h light/12 h dark(12 h/12 h LD)cycle for 2 weeks,with 12 mice in each group.Mice in the normal group were fed in a circadian rhythm chamber in a 12 h LD cycle,mice in the jet-lag group were fed in a 12 h/12 h LD cycle with an 8-hour advanced LD schedule,and mice in the jet lag+SR8278 group were fed in a 12 h/12 h LD cycle with an 8-hour advanced LD schedule and received 25 mg·kg-1 SR8278.At the end of 5 days of intervention,locomotor activity,core body temperature and tear secretion of mice in each group were collected,and the weight of lacrimal gland tissues and size of lacrimal gland cells were measured.Immunohistochemical methods were used for histological evaluation of the extraor-bital lacrimal glands in mice.Lacrimal ribonucleic acid(RNA)was extracted for high-throughput RNA-sequencing analysis containing NR1D1,and the obtained transcriptomic data were used for KEGG and GO functional enrichment analysis.Re-sults Compared with the normal group,the jet-lag group had higher daytime activity,lower nighttime activity,higher daytime core body temperature,and lower nighttime core body temperature,with statistically significant differences(all P＜0.05).Compared with the jet-lag group,the jet-lag+SR8278 group had lower daytime activity,higher nighttime activi-ty,lower daytime core body temperature,and higher nighttime core body temperature,with statistically significant differ-ences(all P＜0.05).Compared with the normal group,the jet-lag group showed a decrease in lacrimal gland weight and tear secretion and an increase in size of lacrimal gland cells,with statistical significance(all P＜0.05);compared with the jet-lag group,the jet-lag+SR8278 group had an increase in lacrimal gland weight and tear secretion and a decrease in size of lacrimal gland cells,with statistical significance(all P＜0.05).Compared with the normal group,the jet-lag group showed a higher expression of NR1D1 in the lacrimal gland at night;compared with the jet-lag group,the jet-lag+SR8278 group showed a lower expression of NR1 D1 in the lacrimal gland at night(both P＜0.05).Bioinformatics analysis showed 947 significantly different genes in the jet-lag group and the jet-lag+SR8278 group,of which 43 are significantly upregulated genes,and 904 are significantly downregulated genes.The Notch signaling pathway has the most significant difference.Conclusion SR8278 effectively enhances the tear secretion function of jet-lagged mice by targeting NR1D1 inhibition.This process may be completed through the Notch signaling pathway.

Objective: To compare the in vitro osteogenic ability of brown adipose stem cells (BADSC) and white adipose stem cells (WADSC), and to provide evidence for further research and clinical application of adipose-derived stem cells. Methods: The brown fat under the scapula of SD rats and the white adipose tissue in the groin were isolated and obtained BADSC and WADSC. The morphology of the cells was observed by an inverted phase contrast microscope, and the cell count was used to detect the proliferative ability. After osteogenic induction, alkaline phosphatase (ALP) staining and alizarin red staining were performed. The expression of the osteogenic marker gene [Runt-related transcription factor-2 (RUNX2), osteocalcin] was detected by quantitative real-time PCR (qPCR). Results: Both BADSC and WADSC were osteogenic. The ALP activity of BADSC was significantly greater than that of WADSC at each time point after osteogenic induction. After 5 weeks of osteogenic induction, BADSC formed a larger area of calcium nodules (accumulated optical density was 92 558±1 507), which was significantly greater than WADSC (accumulated optical density was 52 319±1 786) (t=29.81, P<0.05). The expression of BADSC osteogenic marker genes (RUNX2 and osteocalcin) was significantly higher than that of WADSC (P<0.05). Conclusions Both BADSC and WADSC have the potential for osteogenic differentiation, but BADSC has better osteogenic differentiation ability than WADSC.