Objective: To examine the mediating effect of nighttime sleep duration on pain and frailty among elderly patients with comorbidity of chronic diseases, so as to provide insights into frailty control among the elderly. Methods: Demographic information, pain and nighttime sleep duration of the elderly at ages of 60 years and older were collected from the China Health and Retirement Longitudinal Study 2020. Frailty were evaluated using frailty index. The mediating effect of sleep duration for pain and frailty was analyzed using the Process program compiled by HAYSS and colleagues, and the significance of the mediating role was tested using the Bootstrap test. Results: A total of 2 246 elderly patients with comorbidity of chronic diseases were enrolled, including 1 195 males (53.21%) and 1 051 females (46.79%), with a median age of 65.00 (interquartile range, 8.00) years. There were 504 cases with frailty (22.44%), with a median pain score of 0 (interquartile range, 1.00) points, and a mean nighttime sleep duration of (6.44±1.55) hours. Mediating analysis showed that pain affected frailty directly and positively with the effect value of 0.089 (95%CI: 0.066-0.112), and also affected frailty by nighttime sleep duration directly and positively with the effect value of 0.047 (95%CI: 0.036-0.058), with the mediating effect contributed 34.56% of the total effect. Conclusion Pain can directly or indirectly affect frailty among elderly patients with comorbidity of chronic diseases through nighttime sleep duration.

BACKGROUND:Ischemia microenvironment contributes mostly to the low survival rate of rat bone marrow mesenchymal stem cells after transplantation. Hydrogen sulfide (H2S) can protect various cells and tissue models against apoptosis and injury.
OBJECTIVE:To detect the cellapoptosis and viability, content of H2S in supernatant, and the expression of H2S synthetase after different time of hypoxia and serum deprivation cultivation of rat bone marrow mesenchymal stem cells.
METHODS:The passage 3 rat bone marrow mesenchymal stem cells were divided into five different cultivation time groups:0-, 3-, 6-, 12-and 24-hour groups. After enough hypoxia and serum deprivation cultivated time, the cellapoptosis was detected by SubG1, the cellviability was determined by cellcounting kit-8, the content of H 2S in supernatant was measured by N,N-dimethyl-p-phenylenediamin and the expression of H2S synthetase by RT-PCR and western blot.
RESULTS AND CONCLUSION:Compared to the normal cultivation group, after different hypoxia and serum deprivation cultivated time, the cellapoptosis increased and cellviability decreased significantly. The longer hypoxia and serum deprivation cultivated time caused the more cellapoptosis and the lower cellviability. The contents of H2S and its synthetase were also suppressed by hypoxia and serum deprivation cultivation. The difference was statistical y significant. These findings suggest that hypoxia and serum deprivation cultivation can inhibit the generation of H 2 expression of its synthetase.

BACKGROUND:Bone marrow mesenchymal stem cells (BMSCs) transplantation can promote cardiac repair after myocardial infarction, but it has been limited by the low cellsurvival rate.
OBJECTIVE:To study the effect of hydrogen sulfide (H 2 S) on the BMSCs transplantation for treatment of myocardial infarction.
METHODS:BMSCs were separated and cultivated form Sprague-Dawley rats weighing (100±20) g. The 4th generation cells were used for later experiment, and marked by DAPI at 2 hours before use. Fifty male Sprague-Dawley rats, weighing (200±20) g had been divided into five groups:Sham group (n=10) and four transplantation groups:BMSCs (n=10), H 2 S-BMSCs (n=10), H 2 S (n=10), normal saline (n=10). The myocardial infarction model of four groups was established except of sham group (only thread without ligation). The cardiac function was measured by echocardiogram at 4 weeks after celltransplantation. The col agen in the infarction area was tested by Masson staining.
RESULTS AND CONCLUSION:Severe myocardial fibrosis was found in the normal saline group, with no myocardial regeneration in the infarct area. H 2 S-BMSCs group had less col agen and more cardiac muscle tissue than BMSCs or H 2 S groups. Left ventricular ejection fraction and left ventricular fractional shortening of the H 2 S-BMSCs group were significantly higher than those of the BMSCs or H 2 S groups (P<0.05). The cells survival rate and cardiac function of myocardial infarction rats can be promoted by H 2 S-preconditioned BMSCs transplantation, which is superior to BMSCs or H 2 S alone.