Molecular and Metabolic Mechanism of Low-Intensity Pulsed Ultrasound Improving Muscle Atrophy in Hindlimb Unloading Rats

Low-intensity pulsed ultrasound (LIPUS) has been proved to promote the proliferation of myoblast C2C12. However, whether LIPUS can effectively prevent muscle atrophy has not been clarified, and if so, what is the possible mechanism. The aim of this study is to evaluate the effects of LIPUS on muscle atrophy in hindlimb unloading rats, and explore the mechanisms. The rats were randomly divided into four groups: normal control group (NC), hindlimb unloading group (UL), hindlimb unloading plus 30 mW/cm2 LIPUS irradiation group (UL + 30 mW/cm2), hindlimb unloading plus 80 mW/cm2 LIPUS irradiation group (UL + 80 mW/cm2). The tails of rats in hindlimb unloading group were suspended for 28 days. The rats in the LIPUS treated group were simultaneously irradiated with LIPUS on gastrocnemius muscle in both lower legs at the sound intensity of 30 mW/cm2 or 80 mW/cm2 for 20 min/d for 28 days. C2C12 cells were exposed to LIPUS at 30 or 80 mW/cm2 for 5 days. The results showed that LIPUS significantly promoted the proliferation and differentiation of myoblast C2C12, and prevented the decrease of cross-sectional area of muscle fiber and gastrocnemius mass in hindlimb unloading rats. LIPUS also significantly down regulated the expression of MSTN and its receptors ActRIIB, and up-regulated the expression of Akt and mTOR in gastrocnemius muscle of hindlimb unloading rats. In addition, three metabolic pathways (phenylalanine, tyrosine and tryptophan biosynthesis; alanine, aspartate and glutamate metabolism; glycine, serine and threonine metabolism) were selected as important metabolic pathways for hindlimb unloading effect. However, LIPUS promoted the stability of alanine, aspartate and glutamate metabolism pathway. These results suggest that the key mechanism of LIPUS in preventing muscle atrophy induced by hindlimb unloading may be related to promoting protein synthesis through MSTN/Akt/mTOR signaling pathway and stabilizing alanine, aspartate and glutamate metabolism.

The Abscopal Effects of Cranial Irradiation Induce Testicular Damage in Mice

To investigate whether the abscopal effects of cranial irradiation (C-irradiation) cause testicular damage in mice, male C57BL/6 mice (9weeks of age) were randomly divided into a sham irradiation group, a shielded group and a C-irradiation group and administered sham/shielded irradiation or C-irradiation at a dose rate of 2.33Gy/min (5Gy/d for 4 d consecutively). All mice were sacrificed at 4weeks after C-irradiation. We calculated the testis index, observed testicular histology by haematoxylin-eosin (HE) staining and observed testicular ultrastructure by transmission electron microscopy. Western blotting was used to determine the protein levels of Bax, Bcl-2, Cleaved caspase 3, glial cell line-derived neurotrophic factor (GDNF) and stem cell factor (SCF) in the testes of mice. Immunofluorescence staining was performed to detect the expression of Cleaved caspase 3 and 3β hydroxysteroid dehydrogenase (3βHSD), and a TUNEL assay was used to confirm the location of apoptotic cells. The levels of testosterone (T), GDNF and SCF were measured by ELISA. We also evaluated the sperm quality in the cauda epididymides by measuring the sperm count, abnormality, survival rate and apoptosis rate. The results showed that there was no significant difference in testicular histology, ultrastructure or sperm quality between the shielded group and sham group. Compared with the sham/shielded group, the C-irradiation group exhibited a lower testis index and severely damaged testicular histology and ultrastructure at 4weeks after C-irradiation. The levels of apoptosis in the testes increased markedly in the C-irradiation group, especially in spermatogonial stem cells. The levels of serum T and testicular 3βHSD did not obviously differ between the sham group and the C-irradiation group, but the levels of GDNF and SCF in the testes increased in the C-irradiation group, compared with the sham group. In addition, the sperm count and survival rate decreased in the C-irradiation group, while the abnormality and apoptosis rate increased. Under these experimental conditions, the abscopal effects of C-irradiation induced testicular damage with regard to both structure and function and ultimately decreased sperm quality in mice. These findings provide novel insights into prevention and treatment targets for male reproductive damage induced by C-irradiation.

629 IRRADIATED ESOPHAGEAL SQUAMOUS CELL CARCINOMA CELLS INDUCED THE INCREASE OF TREG BY TGF-β

The infiltration of CD4 + CD25 + Foxp3+ regulatory T cells (Treg) in the tumor microenvironment is one of the main reasons for radiation resistance and tumor recurrence after radiotherapy. It has been established that Treg is more resistant to radiation than other T cells, but the proliferation of immune cells after radiotherapy is affected by other factors, including tumor cells. We studied the effect and mechanism of esophageal squamous cell carcinoma on Treg cells after radiation. Methods After low-dose irradiation, TE-1 cells were co-cultured with normal peripheral blood lymphocytes for 48 hours. Flow cytometry was used to detect Treg/CD4 + T cell frequency. The mRNA expression of TGF-β1 and TGF-β2 in TE-1 was detected by qPCR, and the protein content of TGF-β1 and TGF-β2 in the medium was detected by ELISA. Results Compared with non-irradiation group, the expression of TGF-β1 and TGF-β2 in TE-1 cells of irradiation group increased, and the protein content of TGF-β1 and TGF-β2 in culture medium increased, the difference was statistically significant(P < 0.001). Flow cytometry showed that CD4 + CD25+/CD4 + Tcell and CD4 + CD25 + Foxp3+/CD4 + Tcell were increased in the radiotherapy group after co-culture, and the difference was statistically significant (P < 0.001). Conclusion The expression of TGF-β1 and TGF-β2 in esophageal squamous cell carcinoma cells increased after irradiation, and the frequency of Treg induced by co-culture increased, suggesting that esophageal squamous cell carcinoma cells after radiotherapy can induce the increase of Treg cells, which may be achieved mainly through the mechanism of increasing the secretion of TGF-β1 and TGF-β2.

Studies of Intra-Fraction Prostate Motion During Stereotactic Irradiation in First Irradiation and Re-Irradiation

BackgroundUnderstanding intra-fractional prostate motions is crucial for stereotactic body radiation therapy (SBRT). No studies have focused on the intra-fractional prostate motions during re-irradiation with SBRT. The objective was to evaluate these translational and rotational motions in primary treated patients and in the context of re-irradiation.MethodsFrom January 2011 to March 2020, 162 patients with histologically proven prostate cancer underwent prostate SBRT, including 58 as part of a re-irradiation treatment. We used the continuous coordinates of the fiducial markers collected by an orthogonal X-ray dual-image monitoring system. The translations and rotations of the prostate were calculated. Prostate deviations representing overall movement was defined as the length of the 3D-vectors.ResultsA total of 858 data files were analyzed. The deviations over time in the group of primary treated patients were significantly larger than that of the group of re-irradiation, leading to a mean deviation of 2.73 mm (SD =1.00) versus 1.90 mm (SD =0.79), P<0.001. In the re-irradiation group, we identified displacements of -0.05 mm (SD =1.53), 0.20 mm (SD =1.46); and 0.42 mm (SD =1.24) in the left-right, superior-inferior and anterior-posterior planes. Overall, we observed increasing deviations over the first 30 min followed by a stabilization related to movements in the three translational axes.ConclusionThis is the first study to focus on intrafraction prostate motions in the context of re-irradiation. We observed that intra-fraction prostate motions persisted in the setting of re-irradiation, although they showed a significant reduction when compared with the first irradiation. These results will help to better estimate random errors during SBRT treatment of intra-prostatic recurrence after irradiation.

Irradiated esophageal squamous cell carcinoma cells induced the increase of Treg by TGF-beta.

e16092 Background: The infiltration of CD4+CD25+Foxp3+ regulatory T cells (Treg) in the tumor microenvironment is one of the main reasons for radiation resistance and tumor recurrence after radiotherapy. It has been established that Treg is more resistant to radiation than other T cells, but the proliferation of immune cells after radiotherapy is affected by other factors, including tumor cells. Treg frequency in the tumor microenvironment after radiotherapy has not been defined. We studied the effect and mechanism of esophageal squamous cell carcinoma on Treg cells after radiation. Methods: After 2Gy irradiation, TE-1 cells were co-cultured with normal peripheral blood lymphocytes for 48 hours. Flow cytometry was used to detect Treg/CD4+T cell frequency. The mRNA expression of TGF-β1/2 in TE-1 was detected by qPCR, and the protein content of TGF-β1/2 in the medium was detected by ELISA. Results: Compared with non-irradiation group, the expression of TGF-β1 and TGF-β2 in TE-1 cells of irradiation group increased, and the protein content of TGF-β1 and TGF-β2 in culture medium increased, the difference was statistically significant(P < 0.001). Flow cytometry showed that CD4+CD25+/CD4+Tcell and CD4+CD25+Foxp3+/CD4+Tcell were increased in the radiotherapy group after co-culture, and the difference was statistically significant(P < 0.001). Conclusions: The expression of TGF-β1 and TGF-β1 in esophageal squamous cell carcinoma cells increased after irradiation, and the frequency of Treg induced by co-culture increased, suggesting that esophageal squamous cell carcinoma cells after radiotherapy can induce the increase of Treg cells, which may be achieved mainly through the mechanism of increasing the secretion of TGF-β1/2.

Low-intensity Pulsed Ultrasound Improves Muscle Atrophy in Hindlimb Unloading Rats and its Metabolic Mechanism

Low-intensity pulsed ultrasound (LIPUS) has been proved to promote the proliferation of myoblast C2C12. However, whether LIPUS can effectively prevent muscle atrophy has not been clarified, and if so, what is the possible mechanism. Myostatin (MSTN) is a negtive regulator of skeletal muscle, and inhibition of its expression has a positive effect on the growth and development of skeletal muscle.The aim of this study is to evaluate the effects of LIPUS on muscle atrophyin hind limb unloading rats, and explored the mechanisms. The rats were randomly divided into four groups: normal control group (NC), hind limb unloading group (UL), hind limb unloading plus 30 mW/cm2 irradiation group (UL + 30 mW/cm2), hind limb suspension plus 80 mW/cm2 irradiation group (UL + 80 mW/cm2). The rats were suspended or/and treated with LIPUS for 20 min/d for 28 days. C2C12 cells were exposed to LIPUS at 30 or 80 mW/cm2 for 5 days. After 28 days, LIPUS significantly prevented the decrease of cross-sectional area of muscle fiber and promoted the quality of gastrocnemius muscle. In addition, LIPUS significantly inhibited the content of MSTN in the serum and gastrocnemius muscle of hind limb rats, and its receptor, and promoted myoblast C2C12 proliferation, promoted the stability of alanine, aspartate and glutamate metabolism pathway. These results suggest that the key mechanism of LIPUS in preventing muscle atrophy induced by hind limb unloading may be through inhibiting MSTN and stabilizing alanine, aspartate and glutamate metabolism.

Attenuation of Oxidative Stress-Associated Hematological Alterations and Hepatic Injury Induced by D-Dalactose or γ-Irradiation Using β-Hydroxybutyrate in Male Rats

This work aims to investigate the possible inhibitory action of β-hydroxybutyrate (βOHB) against hematological alterations and hepatic injury associated with oxidative stress caused by D-galactose or γ-irradiation in rats. Six groups of male rats were used as the control, irradiated group (5 Gy), D-galactose (150 mg/kg b.wt), β-hydroxybutyrate (72.8 mg/kg b.wt), γ-irradiation plus βOHB, and D-galactose plus βOHB. Complete blood count and glucose-6-phosphate-dehydrogenase (G6PD) activity were determined in whole-blood samples. In addition, the hepatic malondialdehyde (MDA), nitric oxide (NO), and glutathione (GSH) levels and the superoxide dismutase (SOD) activity were evaluated. Moreover, certain elements were measured in liver tissue (iron (Fe), copper (Cu), and zinc (Zn)). The G6PD activity significantly diminished post exposure to D-galactose or γ-irradiation. In the βOHB, D-galactose, or γ-irradiation groups, liver MDA levels and SOD activity were significantly increased. Meanwhile, NO and GSH levels were significantly increased relative to normal control levels in the γ-irradiation group. The findings showed that βOHB alleviated hematological alterations, enhanced the altered biochemical indices, and modulated the change in Cu, Fe, and Zn elements in D-galactose or γ-irradiation group. These results highlight the role of βOHB as a powerful protective agent against hematological alterations and liver impairment by reducing G6PD-mediated oxidative stress and controlling the measured elements.

Anti-Oxidative and Immuno-Protective Effect of Camel Milk on Radiation-Induced Intestinal Injury in C57BL/6 J Mice

Purpose: The main objective is to investigate the protective effect of camel milk (CM) on radiation-induced intestinal injury. Methods: The C57BL/6 J mice in 2 experiments were assigned into control group (Con), irradiation group (IR), and CM+irradiation group (CM+IR). After receiving the CM via gavage for 14 days, the mice in the first experiment were exposed to 6 Gy X-ray whole body irradiation, and survival rate was compared among the groups. Mice in the second experiment were exposed to 4 Gy irradiation and sacrificed at day 7. The small intestines were collected to examine the histopathological changes and to determine the anti-oxidative index and HMGB1/TLR4 inflammatory pathway. Fasting blood was used to measure serum pro-inflammatory factors. Results: Compared with the IR group, the survival time was prolonged, and survival rate was increased in the CM+IR group. CM increased levels of SOD and GSH and decreased MDA in the jejunum. Furthermore, intestinal protein expression of HMGB1/TLR4 pathway (TLR4, NF-κB, and HMGB1) was up-regulated by CM intervention. CM decreased the serum levels of TNF-α and IL-1β and increased IL-10 level. Conclusions: CM extended the survival time and had a protective effect against radiation-induced jejunum injury by regulation of antioxidant capacity and HMGB1/TLR4/NF-κB/MyD88 inflammatory signaling pathway.

A Novel Brachytherapy Biliary Drainage Catheter Loaded With 125I Seeds in Patients With Malignant Obstructive Jaundice: Preliminary Results Versus Iodine-125 Seed Strands Placement

Background The placement of 125I seeds was a safe method for treating cholangiocarcinoma .The purpose of this study was to compare a novel brachytherapy biliary drainage catheter (BBDC) with an Iodine-125 (125I) seed strand after self-expandable metallic stent(SEMs) implantation in terms of safety and efficacy, as treatments for patients with cholangiocarcinoma of malignant obstructive jaundice (MOJ). Methods From September 2016 to December 2018, We retrospectively enrolled patients with biliary stent implantation after receiving either BBDC loaded with 125I seeds (double-strands irradiation group) or an 125I seed strand treatment (single-strand irradiation group, control group). The outcomes were analyzed regarding the relief of obstructive jaundice, interventional-related complications, stent patency and survival time. ResultsThe success rate of interventional therapy in both groups was 100% and all patients with MOJ were alleviated . The overall complication rates of BBDC group and control group were 23.1% (9 / 39) and 26.5% (9/ 34), respectively (P > 0.05). The median and mean overall stent patency of the BBDC group and the control group were (207 days versus 180 days, 204.212 days versus 186.278 days, p = 0.043). The median and mean overall survivals in the BBDC group were higher than those in the control group (245 days versus 212 days, 244.883 days versus 221.844 days, p = 0.030). ConclusionsThis interim analysis showed that BBDC (double-stranded irradiation) can prolong the stent patency time compared with 125I seed strand treatment (single-stranded irradiation) and had the advantage of reducing jaundice, which seemed to extend survival period.

Effects of Different Methods of Air Disinfection of Computed Tomography Rooms Dedicated to COVID-19 Cases

Objective. To monitor the number of bacterial colonies in the air of computed tomography (CT) room for COVID-19 using different disinfection methods and to identify the most effective method for disinfection and protection of equipment. Methods. Three methods for disinfection using ultraviolet germicidal irradiation (group A), plasma circulation air sterilizer (group B), and ultraviolet germicidal irradiation plus plasma circulation air sterilizer (group C) were utilized to sanitize the air in the CT room dedicated to COVID-19 cases. Single-factor ANOVA was used to evaluate and compare the disinfection effect of the three air disinfection methods; an air microbial sampler was used to sample and measure the number of bacteria in the air of the machine room. Results. The number of bacteria in the air immediately after disinfection was significantly lower than before disinfection ( p < 0.01 ). All three disinfection methods met the disinfection requirement. No significant differences in the number of air bacteria in the machine room immediately after disinfection were observed among the three methods ( p > 0.05 ). In addition, the effect of disinfection after 2 h was compared, and the number of bacteria in group C after 2 h was significantly lower than that in group A and group B. Conclusions. All three disinfection methods have significant disinfection effects. In addition, using ultraviolet disinfection lamps combined with a plasma air disinfection machine to sterilize the air in CT machine room has the best disinfection effect for the longest duration. Therefore, we recommend the combined disinfection method (ultraviolet disinfection lamps plus plasma air disinfection), as well as formulating relevant disinfection management norms, which should thus be the method to use during pandemics.