Effects of warming on seed germination of woody species in temperate secondary forests

Seed germination, a critical stage of the plant life cycle providing a link between seeds and seedlings, is commonly temperature-dependent. The global average surface temperature is expected to rise, but little is known about the responses of seed germination of woody plants in temperate forests to warming. In the present study, dried seeds of 23 common woody species in temperate secondary forests were incubated at three temperature sequences without cold stratification and after experiencing cold stratification. We calculated five seed germination indices and the comprehensive membership function value that summarized the above indicators. Compared to the control, +2 and +4 °C treatments without cold stratification shortened germination time by 14% and 16% and increased the germination index by 17% and 26%, respectively. For stratified seeds, +4 °C treatment increased germination percentage by 49%, and +4 and +2 °C treatments increased duration of germination and the germination index, and shortened mean germination time by 69%, 458%, 29% and 68%, 110%, 12%, respectively. The germination of Fraxinus rhynchophylla and Larix kaempferi were most sensitive to warming without and with cold stratification, respectively. Seed germination of shrubs was the least sensitive to warming among functional types. These findings indicate warming (especially extreme warming) will enhance the seedling recruitment of temperate woody species, primarily via shortening the germination time, particularly for seeds that have undergone cold stratification. In addition, shrubs might narrow their distribution range.

Imaging diagnosis of intravenous leiomyomatosis: an institutional experience

AIM

To review and summarise the clinical and imaging characteristics of intravenous leiomyomatosis (IVL), a rare smooth muscle tumour originating from the uterus.

MATERIALS AND METHODS

Twenty-seven patients with a histopathological diagnosis of IVL who underwent surgery were reviewed retrospectively. All patients underwent pelvic ultrasonography, inferior vena cava (IVC) ultrasonography, and echocardiography before surgery. Computed tomography (CT) with contrast enhancement was performed in patients with extrapelvic IVL. Some patients underwent pelvic magnetic resonance imaging (MRI).

RESULTS

Mean age was 44.81 years. Clinical symptoms were non-specific. IVL was intrapelvic in seven patients and extrapelvic in 20. Preoperative pelvic ultrasonography missed the diagnosis in 85.7% of patients with intrapelvic IVL. Pelvic MRI was useful to evaluate the parauterine vessels. Incidence of cardiac involvement was 59.26%. Echocardiography showed a highly mobile sessile mass in the right atrium with moderate-to-low echogenicity that originates from the IVC. Ninety per cent of extrapelvic lesions showed unilateral growth. The most common growth pattern was via the right uterine vein-internal iliac vein-IVC pathway.

CONCLUSION

The clinical symptoms of IVL are non-specific. For patients with intrapelvic IVL, early diagnosis is difficult. Pelvic ultrasound should focus on the parauterine vessels, the iliac and ovarian veins should be explored carefully. MRI has obvious advantages in evaluating parauterine vessel involvement, which is helpful for early diagnosis. For patients with extrapelvic IVL, CT should be performed before surgery as part of a comprehensive evaluation. IVC ultrasonography and echocardiography are recommended when IVL is highly suspected.

Determining the gluonic gravitational form factors of the proton

The proton is one of the main building blocks of all visible matter in the Universe¹. Among its intrinsic properties are its electric charge, mass and spin². These properties emerge from the complex dynamics of its fundamental constituents-quarks and gluons-described by the theory of quantum chromodynamics^3-5. The electric charge and spin of protons, which are shared among the quarks, have been investigated previously using electron scattering². An example is the highly precise measurement of the electric charge radius of the proton⁶. By contrast, little is known about the inner mass density of the proton, which is dominated by the energy carried by gluons. Gluons are hard to access using electron scattering because they do not carry an electromagnetic charge. Here we investigated the gravitational density of gluons using a small colour dipole, through the threshold photoproduction of the J/ψ particle. We determined the gluonic gravitational form factors of the proton^7,8 from our measurement. We used a variety of models^9-11 and determined, in all cases, a mass radius that is notably smaller than the electric charge radius. In some, but not all cases, depending on the model, the determined radius agrees well with first-principle predictions from lattice quantum chromodynamics¹². This work paves the way for a deeper understanding of the salient role of gluons in providing gravitational mass to visible matter.

[Prognostic analysis of acute pulmonary thromboembolism with newly diagnosed atrial fibrillation]

Objective: To analyze the clinical characteristics and to explore the prognostic factors of acute pulmonary embolism(APE) with newly diagnosed atrial fibrillation(AF). Methods: The medical records of inpatients with APE discharged from Beijing Anzhen Hospital between January 1, 2008, and December 31, 2021 were retrospectively reviewed. The clinical symptoms, complications, laboratory results, echocardiographic parameters, simplified pulmonary embolism severity index (sPESI) and adverse in-hospital outcome were compared between the newly diagnosed AF group and the sinus rhythm group. Logistic regression analysis was used to evaluate the risk factors of adverse in-hospital outcome with APE. Results: Fifty-one patients were included in newly diagnosed AF group and 102 cases in the sinus rhythm group. The patients in newly diagnosed AF group had greater sPESI scores, higher proportion of sPESI≥2 scores, higher incidence of adverse in-hospital outcome as well as longer hospital stay days. Newly diagnosed AF and sPESI≥2 scores were independent predictors affecting adverse in-hospital outcome. The area under ROC curve in newly diagnosed AF combined with sPESI≥2 scores was largest. Conclusions: The APE patients with newly diagnosed AF were more severely ill and prone to in-hospital adverse outcome. Newly diagnosed AF was an independent predictor affecting adverse in-hospital outcome. sPESI≥2 combined with newly diagnosed AF scores had a high predictive value for the occurrence of in-hospital adverse outcome.

[New pathological classification and clinical implications of pituitary neuroendocrine tumors of the 2022 WHO version]

In 2022, the World Health Organization proposed a new classification for pituitary adenomas. The major nomenclature change from the previous edition was the transition from"adenoma"to"pituitary neuroendocrine tumor"(PitNETs). The new classification provided the detailed histological subtypes of PitNETs for routine use of antibodies such as pituitary transcription factors (PIT1, TPIT, SF1, GATA3, and ERα) and hormones. The major PIT1, TPIT, and SF1 lineage-defined PitNETs types and subtypes featured distinct morphologic, molecular, and clinical differences. Unlike the 2017 WHO classification, the 2022 WHO version updated some concepts as follows: (1) Mammosomatotroph, acidophil stem cell tumors and mixed somatotroph/lactotroph tumor represented distinct PIT1-lineage PitNETs; (2) The diagnostic category of PIT1-positive plurihormonal tumor was replaced by the immature PIT1-lineage tumor and the mature plurihormonal PIT1-lineage tumor; (3) The term"metastatic PitNET"was advocated to replace the previous terminology"pituitary carcinoma". The new classification emphasizes the importance of pathological classification of PitNETs. Obviously, accurate pathological interpretation is the key to judge the clinical treatment pathway and prognosis of patients.

Hippo signaling instructs ectopic but not normal organ growth

The Hippo signaling pathway is widely considered a master regulator of organ growth because of the prominent overgrowth phenotypes caused by experimental manipulation of its activity. Contrary to this model, we show here that removing Hippo transcriptional output did not impair the ability of the mouse liver and Drosophila eyes to grow to their normal size. Moreover, the transcriptional activity of the Hippo pathway effectors Yap/Taz/Yki did not correlate with cell proliferation, and hyperactivation of these effectors induced gene expression programs that did not recapitulate normal development. Concordantly, a functional screen in Drosophila identified several Hippo pathway target genes that were required for ectopic overgrowth but not normal growth. Thus, Hippo signaling does not instruct normal growth, and the Hippo-induced overgrowth phenotypes are caused by the activation of abnormal genetic programs.

Perinatal and neurodevelopmental outcome in complicated monochorionic pregnancy after selective fetal reduction: radiofrequency ablation vs microwave ablation

OBJECTIVES

To summarize our experience in the application of radiofrequency ablation (RFA) and microwave ablation (MWA) for selective fetal reduction in complicated monochorionic pregnancies and compare the perinatal outcome of the two techniques.

METHODS

This was a retrospective study of data from a consecutive cohort of all monochorionic twin pregnancies that underwent selective fetal reduction with RFA or MWA at Peking University Third Hospital, Beijing, China from January 2012 to December 2018. All surviving cotwins were followed up to assess their neurodevelopment using the Age & Stage Questionnaire, Chinese version. Perinatal and neurodevelopmental outcomes were compared between the RFA and MWA groups. We also fitted multivariable models to test the association between procedure-related factors and the main perinatal outcomes, including preterm birth (PTB) < 37 weeks' gestation, intrauterine fetal death (IUFD) of the cotwin, adverse outcome (defined as occurrence of IUFD of the cotwin, termination of pregnancy or PTB < 28 weeks) and overall survival.

RESULTS

In total, 45 cases (42 twin and three triplet pregnancies) underwent RFA and 126 cases (105 twin and 21 triplet pregnancies) underwent MWA. The overall survival rates in monochorionic diamniotic twin pregnancies were similar between the RFA and MWA groups (61.0% vs 67.0%; P = 0.494). However, pregnancies whose indication for fetal reduction was selective intrauterine growth restriction or twin reversed arterial perfusion had higher overall survival rates (75.5% and 82.6%, respectively) compared with those in other indication groups. A total of 104 children were followed up (20 in the RFA group and 84 in the MWA group); four (20.0%) and eight (9.5%) children were assessed as having overall developmental delay in the RFA and MWA groups, respectively, with no significant difference between the two groups. Multivariable analyses showed that procedure indication, number of ablation cycles and gestational age at procedure were associated significantly with the main perinatal outcomes.

CONCLUSIONS

RFA and MWA for selective fetal reduction in complicated monochorionic pregnancies can achieve similar overall survival rate and neurodevelopmental outcome, but MWA is associated with a lower risk of preterm birth. Moreover, procedure-related factors are associated significantly with perinatal outcome. © 2022 International Society of Ultrasound in Obstetrics and Gynecology.

[Analysis of solitary rectal ulcer syndrome in 7 children]

Objective: To analyze the clinical features, treatment and prognosis of solitary rectal ulcer syndrome (SRUS) in children. Methods: The clinical data of 7 children who were diagnosed with SRUS in Department of Gastroenterology in Guangzhou Women and Children' Medical Center from January 2019 to December 2021 were retrospectively analyzed. The clinical data including general demographics, clinical presentations, endoscopic and histologic features, treatment and outcome were extracted from hospital medical records. Results: The 7 patients were all males, and the age of onset was 6-12 years. The course before diagnosis was 2-36 months. The most common symptom was rectal bleeding (6 cases) and most common findings at initial colonoscopy were ulcer in 3 cases and protuberance in 4 cases, both located only in rectum. The intestinal histopathology of 5 cases showed characteristic fibromuscular obliteration of lamina propria. Five children were treated with mesalamine granules or suppositories, and 2 cases underwent local excision. The follow-up lasted for 5-24 months and found symptoms relieved in 5 cases, improved in 1 case, and no remission in 1 case. Colonoscopy after the treatment was performed in 5 children, among whom 2 cases achieved mucosal healing. Conclusions: SRUS in children is mainly presented with rectal bleeding, and has characteristic histological change of ulcer and protuberance in endoscopy. Pathology is crucial for diagnosis and differential diagnosis. Both the medical and surgical treatment are effective for SRUS.

[Analysis of upper airway morphology and laryngopharyngeal reflux in obese patients with OSA]

Objective: To investigate the morphological characteristics of upper airway and laryngopharyngeal reflux in obese patients with obstructive sleep apnea (OSA). Methods: A retrospective analysis was performed on the clinical data of 284 adult patients who underwent polysomnography (PSG) from April 2020 to April 2021 in the Department of Otorhinolaryngology, Head and Neck Surgery, Zhongnan Hospital of Wuhan University, including 83 males and 201 females, aged (32.70±7.74) years. Patients were divided into obese group (n=234) and non-obese group (n=50) according to body mass index (BMI). Patients were divided into mild OSA group, moderate OSA group, severe OSA group and extremely severe OSA group by PSG.The results of sleepiness and laryngopharyngeal reflux questionnaire, nasolaryngoscopy and polysomnography were compared in each group. SPSS (version 22.0) software was used in data analysis. Results: Compared with the non-obese OSA group, the lymphoid hyperplasia of tongue root was more heavy in the obese OSA group, and Mueller's maneuver showed that the left-right lateral collapse of the velopharyngeal plane was more serious. Meanwhile, the scores of reflux symtom index (RSI) and reflux finding score (RFS) in the obese OSA group were significantly increased, and the scores of RSI and RFS increased with the increase of OSA severity. The main respiratory events in obese patients with OSA were obstructive hypopnea, their apnea-hypopnea indices(AHI) during REM (AHI_REM) was significantly higher than non-REM (AHI_NREM), and they had lower average blood oxygen saturation. Yet, there was no significant difference in the lowest blood oxygen saturation between the two groups. Conclusions: Our study suggests that lateral pharyngeal wall stenosis in velopharyngeal plane and the lymphoid hyperplasia of tongue root in glossopharyngeal plane occurs more frequently in obese patients with OSA. Laryngopharyngeal reflux is significantly increased in obese patients, and OSA increases laryngopharyngeal reflux in obese patients.

Ensemble forecast experiments of summertime sea ice in the Arctic Ocean using the TOPAZ4 ice-ocean data assimilation system

Precise information on sea ice thickness (SIT) and its prediction at medium-range (2-week) timescale is crucial for the safe maritime navigation in the Arctic Ocean. In this study, we investigate the sensitivity of medium-range prediction skill of summertime SIT distribution in the Arctic marginal seas to atmospheric forecast data, using the 51-member ECMWF operational ensemble prediction system (EPS). For a synoptic-scale cyclone event occurred in July 5-6, 2015, two-week probabilistic forecast experiments were conducted with the TOPAZ4 ice-ocean forecast system, starting on 1st July. The ensemble correlation analysis between the forecast SIT and the meteorological parameters shows that the forecast error of SIT distribution is sensitive to the sea ice drift speed until 1-week, indicating that realistic sea ice drift improves the sea ice thickness prediction. On the other hand, beyond 1 week lead, the forecast error of SIT distribution is more sensitive to surface heat flux rather than sea ice drift. The surface heat flux signal is confined to the sea ice edge region, where the shortwave radiation flux is related to the SIT change through the sea ice melting process. The shortwave radiation flux in the sea ice edge is mostly determined by the sea ice distribution, suggesting that the skillful prediction of sea ice distribution, which is largely affected by synoptic-scale disturbance, at shorter lead times indirectly affects the medium-range forecast skill. A comparison of different ensemble perturbation techniques shows that the prediction skill is better at shorter lead times (up to 1 week), when using an atmospheric EPS rather than the random perturbations used in the operational forecast system, but the random perturbations are advantageous beyond 1 week. Thus, the application of the EPS to an ice-ocean coupled forecast system leads to a more precise sea ice prediction on medium-range timescale, which we expect to become of practical use for the optimum shipping route in the Arctic Ocean.

[Current status of regular exercise and influencing factors in 18-64 year old labor force population in Beijing]

Objective: To understand the regular exercise status and influencing factors in 18-64 year-old labor force population in Beijing, and provide evidences for behavioral intervention. Methods: Data were collected from Beijing Adult Non-communicable and Chronic Diseases and Risk Factors Surveillance Program from August to December, 2017. The stratified cluster sampling method was used to select 13 240 survey subjects throughout the city. The valid sample size included in this study were 11 604 persons aged 18 to 64 years. Questionnaire was used to collection the information about basic demographic characteristics, chronic disease history and physical activity prevalence of the study subjects. The body height and weight were measured by standard methods. Fasting venous blood samples were collected for the detection of fasting blood glucose, blood lipids and other biochemical indicators. Software SPSS 20.0 was used fort complex sampling sample weighting and data analysis. Results: The proportions of the study subjects who did regular exercise and never had leisure-time activity in 18-64 year-old labor force population in Beijing were 23.74% (95%CI: 21.51%-26.12%) and 64.34% (95%CI: 61.66%-66.94%) respectively; The average daily physical activity time was 23.44 min (95%CI: 21.16-25.71), and the total daily sedentary behavior time was 6.96 hours (95%CI: 6.80-7.13). With the increase of age, the proportions of the study subjects who did regular exercise and never had leisure-time activity increased (P=0.006, P<0.001). With the increase of educational level, the proportion of those who did regular exercise increased (P<0.001), and the proportion of those who never had leisure-time activity decreased (P<0.001); the higher the level of physical activity, the higher the regular exercise proportion (P<0.001); the proportions of employed people who did regular exercise was lower than those in unemployed people (P<0.001); the proportions of women never had leisure-time activity was higher than those in men (P=0.024). The results of multivariate analysis showed that older age and higher education level were positive factors for regular exercise (35- years old: OR=0.653, 95%CI: 0.530-0.804, P<0.001; 50-64 years old: OR=0.695, 95%CI: 0.560-0.864, P=0.001; high school/technical secondary school/technical School: OR=0.679, 95%CI: 0.593-0.777, P<0.001; college graduation: OR=0.478, 95%CI: 0.387-0.590, P<0.001; bachelor degree and above: OR=0.435, 95%CI: 0.347-0.546, P<0.001), while employment (OR=1.631, 95%CI: 1.330-2.000, P<0.001) and married/cohabitation (OR=1.340, 95%CI: 1.093-1.644, P=0.038) were negative factors for regular exercise. Conclusions: The rate of regular exercise in 18-64 year-old labor force population in Beijing needs to be improved. Older age and high educational level were positive factors for regular exercise, while being married and employed were negative factors for it.

[Investigation on knowledge, attitude and behavior of salt reduction in adults of Beijing in 2017]

Objective: To explore the knowledge, attitude and behavior of salt reduction in adults of Beijing in 2017. Methods: Based on the monitoring data of chronic diseases and corresponding risk factors in adults of Beijing in 2017, the indicators of salt reduction knowledge, attitude and behavior of 13 240 participants aged 18-79 years old were analyzed. The awareness rate, attitude support rate and behavior rate were calculated by complex weighting method, and compared among different age groups, genders, residential areas, and history of hypertension. The proportion of people taking various salt reduction measures to the total number of people was compared. Results: The awareness rate of recommended daily salt intake, the awareness of hypertension caused or aggravated by more salt intake, the attitude support rate and behavior rate of adults were 31.77%, 88.56%, 90.27% and 53.86%, respectively. After weighted adjustment, the awareness rate of recommended daily salt intake was 31.08%, which increased with age (χ²_trend=431.56, P<0.001) and education level (χ²_trend=95.44, P<0.001). The awareness rate of women was higher than that of men (χ²=118.89, P<0.001), and the awareness rate of population in urban areas was higher than that of population in suburban areas (χ²=34.09, P=0.001). The awareness rate of hypertension caused or aggravated by eating more salt was 86.73%. The support rate of salt reduction attitude was 90.45%. The rate of salt-reducing behavior was 54.05%. Among different salt reduction measures, reducing salt when cooking was the most common measure (52.41%), while the least common one (35.22%) was using low sodium salt. Logistic regression model analysis showed that the gender, age, education level, self-reported history of hypertension, awareness of salt recommendation, awareness of hypertension caused or aggravated by eating more salt, and salt reduction attitude were significantly associated with salt reduction behavior. Conclusion: In 2017, adults in Beijing have a basic understanding of the impact of high-salt diet on health and support salt reduction, but the rate of salt reduction behavior is still relatively low. There are obvious gender and age differences, and the salt reduction measure is simple. Targeted measures should be taken to promote the formation of salt reduction behavior.

[Analysis of the current status and related factors of oral nutritional supplements intake among 18-79 years old in Beijing in 2017]

Objective: To understand the current status of taking nutrient supplements for residents aged 18 to 79 years old in Beijing and its related factors. Methods: Data were gathered from the 2017 Beijing Non-communicable and Chronic Disease Surveillance Program. Multiple classified cluster sampling method was used, and participants aged 18-79 were sampled from 16 districts. The questionnaire included chronic diseases and related risk factors, health knowledge, and oral nutritional supplements within 12 months. Multivariate logistic regression models were established to analyze associated factors that affect the intake of nutrient supplements. Results: The weighted prevalence of supplements use was 13.1% among 12 696 subjects within the past 12 months. The proportions of multivitamins (4.7%), B vitamins (4.5%), and folic acid (3.2%) were higher. The prevalence of supplement use of young people (18-39 years old) and the elderly (60-79 years old) was higher than middle-aged people (40-59 years old) (χ²=54.09, P<0.001). Except for the age group of 70-79 years old, the consumption rate of women was significantly higher than that of men (P<0.05). After adjusting age and sex, among patients with hypertension, diabetes, or dyslipidemia, the control rates of blood pressure, glucose and lipids of patients who take nutrient supplements were higher than those who do not (P<0.05). And participants who took nutrient supplements had a more heightened awareness rate of health knowledge, such as the hazards of smoking and second-hand smoke, and recommended amount of salt per day (P<0.001). The multi-factor logistic analysis found that nutrient supplement-related factors include women, old age, higher education level, living in urban, insufficient physical activity, sleeping problems, active physical examination, blood pressure control among patients, and health knowledge (P<0.05). Conclusions: The factors of nutrient supplements use were related to sex, age, education level, health status, and health literacy. We should pay attention to key populations and guide them to establish the correct concept of taking nutrient supplements.

A 2-year locomotive exploration and scientific investigation of the lunar farside by the Yutu-2 rover

The lunar nearside has been investigated by many uncrewed and crewed missions, but the farside of the Moon remains poorly known. Lunar farside exploration is challenging because maneuvering rovers with efficient locomotion in harsh extraterrestrial environment is necessary to explore geological characteristics of scientific interest. Chang'E-4 mission successfully targeted the Moon's farside and deployed a teleoperated rover (Yutu-2) to explore inside the Von Kármán crater, conveying rich information regarding regolith, craters, and rocks. Here, we report mobile exploration on the lunar farside with Yutu-2 over the initial 2 years. During its journey, Yutu-2 has experienced varying degrees of mild slip and skid, indicating that the terrain is relatively flat at large scales but scattered with local gentle slopes. Cloddy soil sticking on its wheels implies a greater cohesion of the lunar soil than encountered at other lunar landing sites. Further identification results indicate that the regolith resembles dry sand and sandy loam on Earth in bearing properties, demonstrating greater bearing strength than that identified during the Apollo missions. In sharp contrast to the sparsity of rocks along the traverse route, small fresh craters with unilateral moldable ejecta are abundant, and some of them contain high-reflectance materials at the bottom, suggestive of secondary impact events. These findings hint at notable differences in the surface geology between the lunar farside and nearside. Experience gained with Yutu-2 improves the understanding of the farside of the Moon, which, in return, may lead to locomotion with improved efficiency and larger range.

[Effect of lipopolysaccharide-stimulated exosomes from human dental pulp stem cells combined with stromal cell-derived factor-1 on dental pulp regeneration]

Objective: To investigate the effect of exosomes from mild-inflammation- stimulated human dental pulp stem cells (hDPSC) combined with stromal cell-derived factor-1 (SDF-1) on dental pulp regeneration in rats. Methods: Primary hDPSCs were isolated, cultured and then stimulated by using lipopolysaccharide (LPS). The exosomes from the hDPSCs with (L-EXO) or without (N-EXO) LPS were extracted by overspeed differential centrifugation and were identified by transmission electron microscopy and Western blotting. Forty SD rats, aged 6-8 weeks, were equally divided into S group (SDF-1 alone), L+S group (L-EXO combined with SDF-1), N+S group (N-EXO combined with SDF-1) and blank control group (no substance implanted into the root canal) by random number table method. Bilateral mandibular first molars were used as the experimental teeth to establish pulpless root canal models and different contents were implanted into the root canals according to the groups. All rats were over-anesthetized and sacrificed at the 30th day after content implantation. Bilateral mandibular tissues were taken for histological evaluation by means of HE, Masson and immunohistochemical stainings. Results: The HE staining showed new pulp-like tissue in the root canals of all three experimental groups. The amount of new tissues and the number of cells in the tissues were greatest in L+S group and least in S group. Masson staining showed that the mineralized tissue in L+S group was arranged longitudinally along the root canal wall and the collagen fibers were arranged in an orderly fashion, while those in N+S group showed an irregular and disordered distribution. Quantitative analysis of the area of neovascularization in each group showed that the density of vessels in the L+S group [(2.03±0.65)%] was significantly higher than that in the S group [(0.65±0.05)%] and the N+S group [(1.06±0.38)%] respectively (F=5.879, P<0.05). Immunohistochemical staining showed that the expression of CXC chemokine receptor 4 (CXCR4) was significantly lower in S and L+S groups than in N+S group, with a statistically significant difference (F=8.633, P<0.01). Conclusions: Exosomes secreted by hDPSCs combined with SDF-1 might increase the amount of new tissue in the root canal and the density of blood vessels in the tissue. L-EXO showed a stronger effect than N-EXO did. The combination of L-EXO with SDF-1 might result in more regular arrangement of mineralized tissue and collagen fibers in the regenerative tissues.

The synergistic effect of palmitic acid and glucose on inducing endoplasmic reticulum stress-associated apoptosis in rat Schwann cells

OBJECTIVE

Diabetic peripheral neuropathy (DPN) is a common long-term complication of diabetes mellitus accompanied with hyperglycemia and hyperlipidemia. Both high blood glucose and high blood lipids are key pathogenies for DPN. This research aims to investigate whether the combination of glucose (Glu) and palmitic acid (PA) played a synergistic role in the pathogenesis of DPN.

MATERIALS AND METHODS

The proliferation rate of Rat Schwann cell line RSC96 cells stimulated by different concentrations of Glu and PA were analyzed by CCK-8 assay. After the IC50 was detected for each drug, the RSC96 cells were divided into control, Glu, Glu+PA, PA, and BSA groups. The apoptosis of RSC96 cells in different groups were detected by flow cytometry. The effects of Glu and/or PA on endoplasmic reticulum (ER) stress-associated apoptotic signaling pathways were determined by Western blot and qPCR.

RESULTS

Both Glu and PA showed similar inhibition on the proliferation of RSC96 cells in a dose-dependent manner. However, PA induced stronger apoptosis of RSC96 cells than glucose and significantly increased the levels of X-box-binding protein-1 (XBP1), C/EBP homologous protein (CHOP), and eIF2α phosphorylation, which are key proteins regulating endoplasmic reticulum (ER) stress-associated apoptotic signaling pathways. The combination of Glu and PA induced the strongest apoptosis in RSC96 cells and also activated ER stress-associated apoptotic signaling pathways. These results verified the synergistic effect of Glu and PA on inducing ER stress-associated apoptosis in RSC96 cells, and PA even induced stronger apoptosis in RSC96 cells than Glu.

CONCLUSIONS

The present research indicated that hyperglycemia and hyperlipidemia might exert a synergistic damage during the pathogenesis of DPN, suggesting that blood lipid control is as important as blood glucose control for DPN patients.