Objective To evaluate the effects of hydrogen-rich saline on the early diabetic neuropathic pain (DPN) in rats.Methods Healthy male Sprague-Dawley rats,aged 8 weeks,weighing 180-220 g,were used in the study.DPN model was made by intraperitoneal injection of 1％ streptozocin (STZ) 65 mg/kg.Twelve diabetic rats were randomly divided into 2 groups (n =6 each) using a random number table:DPN group and hydrogen-rich saline group (HRS group).Another 6 normal rats were randomly collected as control group (group C).At 14 days after STZ injection,hydrogen-rich saline 5 ml/kg was injected intraperitoneally once a day for 14 consecutive days in HRS group,while C and DNP groups received the equal volume of normal saline.Mechanical paw withdrawal threshold to yon Frey stimuli (MWT) and paw withdrawal latency to nociceptive thermal stimulation (TWL) were measured at 2 days before STZ injection (To) and 7,14,21 and 28 days after STZ injection (T1-4).The motor nerve conduction velocity (MNCV) of the right hindlimb and distal motor latency was measured after pain threshold was measured at T4.After measurement of neurological function was completed,tumor necrosis factor-α (TNF-α) and i nterleukin-6 (IL-6) contents (by ELISA) and nuclear factor kappa B (NF-κB) activity (by immuno-histochemistry) were detected.Results Compared with group C,MNCV was significantly decreased,the motor latency was prolonged,MWT was decreased at T1-T4,TWL was shortened at T2-T4,TNF-a and IL-6 contents were increased,and NF-κB activity was enhanced in DNP and HRS groups (P ＜ 0.05).Compared with group DNP,MNCV was significandy increased,the motor latency was shortened,MWT was increased at T3.4,TWL was prolonged at T4,TNF-a and IL-6 contents were decreased,and NF-κB activity was weakened in group HRS (P ＜ 0.05).Conclusion Hydrogen-rich saline can relieve the early DPN through inhibiting NF-κB signaling pathway in rats.

AIM: The aim of this study was to observe the cardiac performance in 2-week or 4-week levothyroxine(T4)-induced cardiac hypertrophy and to elucidate the possible underlying mechanism of cardiac hypertrophy transition to heart failure in T4 treatment rats.METHODS: The blood pressure and pulse rate were measured by tail-cuff technique.The cardiac output and the preload-cardiac output were measured in working heart mode.The shortening of unloading contraction in cardiomyocytes was observed by an edge-detector system.RESULTS: Resting heart rate in T4 treatment rats increased significantly and the width of cardiomyocytes widened in T4 rats,but the length of cardiomyocytes had no difference compared with control values.The cardiac output in 2-week T4 group was higher than that in control group.The cardiac output increased when the preload increased from 5 mmHg to 15 mmHg.The unloading shortening amplitude at 1 Hz and 2 Hz increased in 2-week T4 group.No difference between 2-week T4 group and control group at 4 Hz was observed.When the stimulating frequency increased from 1 Hz to 4 Hz,the shortening amplitude also increased in control cardiomyocytes,but decreased in 2-week or 4-week T4 group.The shortening amplitude increased further in 4-week T4 group as compared with that in control.The time to peak shortening and time from peak shortening to 75% relaxation reduced at each frequency in 2-week and 4-week T4 group.The shortening and relaxation rates in 2-week or 4-week T4 group were higher than those in control group at 1 Hz and 2 Hz.The shortening and relaxation rate kept higher at 4 Hz in 2-week T4 group,but showed no difference with control at 4 Hz in 4-week T4 group.CONCLUSION: These above results suggest that shortening amplitude-frequency relationship of cardiomyocytes in 4-week T4 rats is earlier to be altered than cardiac performance in working heart.

Objective To evaluate the effects of hydrogen on oxidative stress injury induced by high glucose in Schwann cells and its relationship with PARP-1-dependent cell death (parthanatos).Methods Primary rat Schwann cells were cultured in 96-well plate (1×104 cells/ml,200 μl/well) or in 6-well plate (1 × 106 cells/ml,2 ml/well) with RSM culture medium and were randomly divided into 5 groups (n=30 each):control group (group C),hydrogen group (group H2),high glucose group (group HG),high glucose plus hydrogen group (group HG+H2) and high osmotic control group (group M).The cells were cultured in the common culture medium in C,HG and M groups.The cells were cultured in hydrogen-rich culture medium in H2 and HG + H2 groups.In HG and HG + H2 groups,50 mmol/L of glucose was added to the culture medium.In C and H2 groups,the equal volume of normal saline was added to the culture medium.In M group,mannitol 44.4 mmol/L was added to the culture medium.The cells were then incubated for 48 h.After 48 h of incubation,the cell viability was measured using CCK-8 assay,intracellular reactive oxygen species (ROS) level was detected by flow cytometry,the concentration of 8-hydroxy-2-deoxy Guanosine (8-OHdG) was determined by ELISA,and the expression of poly (ADP-ribose)-polymerase-1 (PARP-1),cleaved-PARP-1,poly (ADP-ribose) (PAR),and apoptosis-inducing factor (AIF) in the total protein and nucleus was measured by Western blot.PARP-1 activity (cleaved-PARP-1/PARP-1) and AIF nuclear translocation were recorded.Results Compared with C and H2 groups,the cell viability was significantly decreased,and PARP-1 activity,expression of ROS,8-OhdG and PAR,and AIF nuclear translocation were increased in HG and HG + H2 groups.Compared with HG group,the cell viability was significantly increased,and PARP-1 activity,expression of ROS,8-OhdG and PAR,and AIF nuclear translocation were decreased in HG+H2 group.There was no significant difference in each parameter between M and C groups.Conclusion Hydrogen can reduce oxidative stress injury induced by high glucose in Schwann cells,and the mechanism is related to inhibition of parthanatos.

Objective To investigate the protective effects and underlying molecular mechanisms of hydrogen (H2) on high glucose-induced poly (ADP-ribose) polymerase-1 (PARP-1) dependent cell death (PARthanatos) in primary rat Schwann cells. Methods Cultured primary rat Schwann cells were randomly divided into five groups: blank control group (C group), H2 control group (H2 group), high osmotic control group (M group), high glucose treatment group (HG group), and H2 treatment group (HG+H2 group). The cells in H2 group and HG+H2 group were cultured with saturated hydrogen-rich medium containing 0.6 mmol/L of H2, and those in three control groups were cultured with low sugar DMEM medium containing 5.6 mmol/L of sugar, and the cells in HG and HG+H2 groups were given 44.4 mmol/L of glucose in addition (the medium containing 50 mmol/L of glucose), the cells in C group and H2 group were given the same volume of normal saline, and the cells in M group were given the same volume of mannitol. Cytotoxicity was evaluated using lactate dehydrogenase (LDH) release rate assays after treatment for 48 hours in each group. The contents of peroxynitrite (ONOO-) and 8-hydroxy-2-deoxyguanosine (8-OHdG) reflecting oxidative stress injury and DNA damage were detected by enzyme linked immunosorbent assay (ELISA). Poly (ADP-ribose) (PAR) protein expression was analyzed by Western Blot, and immunofluorescence staining was used to determine the nuclear translocation of the apoptosis-inducing factor (AIF). Results The cytotoxicity in HG and HG+H2 groups was significantly increased as compared with that of C group [LDH release rate: (61.40±2.89)%, (42.80±2.32)% vs. (9.92±0.38)%, both P < 0.01], the levels of ONOO- and 8-OHdG were markedly elevated [ONOO- (ng/L): 853.58±51.00, 553.11±38.66 vs. 113.56±14.22; 8-OHdG (ng/L): 1 177.37±60.97, 732.06±54.29 vs. 419.67±28.77, all P < 0.01], and the PAR protein expression was up-regulated (A value: 0.603±0.028, 0.441±0.010 vs. 0.324±0.021, both P < 0.01). The cytotoxicity, the levels of ONOO- and 8-OHdG, and PAR expression in HG+H2 group were significantly lower than those of the HG group (all P < 0.01). There were no significant differences in above parameters between H2 group as well as M group and C group. It was shown by immunofluorescence that AIF was expressed in the cytoplasm in C group, H2 group and M group, AIF was expressed in the whole cell in HG group, and the expression in the nucleus was particularly increased. A small amount of AIF expression was found in the nucleus of HG+H2 group, which indicated that high glucose could promote the AIF nuclear translocation, and that hydrogen-rich medium could prevent the process of translocation. Conclusions High glucose levels could enhance DNA damage that enhance PARthanatos in primary rat Schwann cells. However, H2 can not only reduce DNA damage of injured cells, but also inhibit the special death process, reduce the cell toxicity, all of which have protective effects.

Objective To evaluate the effect of hydrogen-rich saline on Toll-like receptor 4 (TLR4) /nuclear factor kappa B (NF-κB) signaling pathway in the sciatic nerve of rats with diabetic neuropathic pain (DNP).Methods Pathogen-free male Sprague-Dawley rats, aged 8 weeks, weighing 180-210 g, were used in the study.DPN model was established by intraperitoneal injection of 1％ streptozocin (STZ) 65 mg/kg.Twenty-four diabetic rats were randomly divided into 2 groups (n =12 each) using a random number table: DPN group and hydrogen-rich saline group (HRS group).Another 12 normal rats were randomly selected and served as control group (group C).At 14 days after STZ injection, hydrogenrich saline 5 ml/kg was injected intraperitoneally once a day for 14 consecutive days in group HRS, while the equal volume of normal saline was given in C and DNP groups.Mechanical paw withdrawal threshold to yon Frey stimuli (MWT) and thermal paw withdrawal latency (TWL) were measured at 2 days before STZ injection (T0) , and 7, 14, 21 and 28 days after STZ injection (T1-4).The motor nerve conduction velocity (MNCV) of the right hindlimb was measured after pain threshold was measured at T4.After measurement of neurological function was completed, the expression of TLR4 and NF-κB was detected in the sciatic nerve (by Western blot) , the tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6) contents in sciatic nerves were measured by enzyme-linked immunosorbent assay, and the neuronal apoptosis was detected by TUNEL.The apoptosis index was calculated.Results Compared with group C, the MWT was significantly decreased at T1-4, TWL was shortened at T2-4, and MNCV was decreased at T4, the expression of TLR4 and NF-κB, contents of TNF-α and IL-6, and apoptosis index were increased in HRS and DNP groups (P＜0.05).Compared with group DNP, the MWT was significantly increased, and TWL was prolonged at T3,4 MNCV was increased T4, and the expression of TLR4 and NF-κB, contents of TNF-α and IL-6, and apoptosis index were decreased in group HRS (P＜ 0.05).Conclusion Hydrogen-rich saline can mitigate DNP through blocking TLR4/NF-κB signaling pathway in the sciatic nerve of rats.

Aerospace physiology is an important part of aerospace medicine.There are some problems existing in the current practice classes.Microlecture is a new kind of teaching methods.With its advantages, microlecture improved the teaching efficiency, and played a good role in the practice classes for undergraduate students, successfully solving part of the problems and promoting the teaching reform.The microlecture, as an auxiliary means, provides a new way for practice class of aerospace physiology.It`s suggested to be popularized in undergraduate teaching of aerospace medicine.

Objective: To observe the effect of the (p)ppGpp synthase gene (relA) on the heteroresistance of colistin against Acinetobacter baumannii. Methods: The relA gene in Acinetobacter baumannii ATCC19606 was knocked out by Red homologous recombination technique. The biofilm formation of Acinetobacter baumannii was observed by crystal violet staining. The change of heterogeneous colonies of Acinetobacter baumannii under the action of colistin was detected by population analysis profiles (PAP) and the heterogeneity was calculated. The killing curve was used to detect the formation of persistent bacteria in Acinetobacter baumannii under the action of colistin. Results: The relA gene in Acinetobacter baumannii was successfully knocked out, and the relA knockout strain ATCC19606-ΔrelA was obtained. After relA gene knockout, the biofilm formation of Acinetobacter baumannii decreased significantly. After relA gene knockout, Acinetobacter baumannii significantly reduced the heterogeneous colonies and persistent bacteria formation under the action of colistin. Conclusion: The bacterial stringent reaction (p) ppGpp synthase relA may be an important factor affecting the heteroresistance of Acinetobacter baumannii to colistin.

OBJECTIVEOver the last few decades, diabetic cardiomyopathy has been identified as a significant contributor in cardiac morbidity. However, the mechanisms of diabetic cardiomyopathy have not been clarified.

METHODSIn the present study, a diabetic rat model was induced by the intraperitoneal injection of streptozotocin. The myocardial CD147 expression and extent of glycosylation, as well as thematrixmetalloproteinases(MMPs) expression and activity, were observed in the diabetic and synchronous rats.

RESULTSThe results showed that CD147 located on sarcolemma of cardiomyocytes. The myocardial CD147 expression and glycosylation were significantly increased in the diabetic rats as compared with the control. Expression of MMP-2 protein, MMP-2 and MMP-9 activity were also increased in left ventricular myocardium in the diabetic rats. Tamoxifen only inhibited the enhanced expression of myocardial CD147 in the diabetic rats, but not in synchronous control rats. Tamoxifen inhibited glycosylation of myocardial CD147 in both diabetic and control rats. The inhibition of tamoxifen on CD147 glycosylation was stronger than on the expression in the myocardium. The extent of myocardial CD147glycosylation was positively related toMMP-2 and MMP-9 activity. Tamoxifen induced an inhibition of myocardial MMP-2 and MMP-9 activity in the control and diabetic rats.

CONCLUSIONThese results indicate that myocardial CD147 expression, especially the extent of glycosylation, regulates MMP-2 and MMP-9 activity, then accelerates cardiac pathological remodeling inducing diabetic cardiomyopathy. Tamoxifen inhibits myocardial CD147 glycosylation and further depress the activity of MMPs. Therefore, tamoxifen may protect the diabetic rats against diabetic myocardium.

Animals ; Basigin ; metabolism ; Diabetes Mellitus, Experimental ; complications ; Diabetic Cardiomyopathies ; drug therapy ; Glycosylation ; Heart ; drug effects ; Matrix Metalloproteinase 2 ; metabolism ; Matrix Metalloproteinase 9 ; metabolism ; Myocardium ; metabolism ; Myocytes, Cardiac ; cytology ; Rats ; Sarcolemma ; metabolism ; Tamoxifen ; pharmacology

Fatigue occurs when the interval of intermittent tetanic contraction of skeletal muscle is shortened to a certain degree and the contractile tension declines. After fatigue, prolongation of the contraction interval can make the contractile tension recover. In atrophic soleus, the recovery rate is slower. It has been shown that a decrease in the contractile tension is caused by the inhibition of the myofibrils and sarcoplasmic reticulum Ca(2+) release channels during fatigue. So the mechanism of the recovery of contractile tension is the recovery of the inhibited myofibrils and sarcoplasmic reticulum Ca(2+) release channels. But how the inhibition affects the recovery course is still unclear. To specify the factors modulating the recovery rate after intermittent tetanic fatigue in soleus, and to seek the reasons for the decrease in recovery rate in atrophic soleus, we observed the recovery time course of different types of fatigue in isolated soleus muscle strips. The 10% or 50% decrease in the maximal tetanic contractile tention (P(0)) was defined respectively as slight or moderate fatigue. After short-term (S10P, 10 s) and long-term (L10P, 300 s) slight fatigue, the tetanic contractile tension recovered to nearly 100% P(0) at the 20th minute. In both slight fatigue groups, perfusion with 10 mumol/L of ruthenium red (an inhibitor of Ca(2+) release channels in sarcoplasmic reticulum) slowed down the recovery rate. It was suggested that slight fatigue only induced inhibition of myofibrils. After short-term (S50P, 60 s) or long-term (L50P, 300 s) moderate fatigue, the tetanic contractile tension at the 20th minute recovered to about 95% P(0) in S50P group and 90% P(0) in L50P group, respectively. The recovery rate in L50P group was significantly lower than that in S50P group. So the recovery rate after moderate fatigue was related to the tetanic contraction duration. In both moderate fatigue groups, perfusion with 5 mmol/L of caffeine (an opener of Ca(2+) release channels in sarcoplasmic reticulum) resulted in nearly 100% recovery at the 5th minute. It was suggested that moderate fatigue induced inhibition of myofibrils and sarcoplasmic reticulum Ca(2+) release channels. In 1-week tail-suspended rats, soleus muscles showed a 40% of atrophy. After slight fatigue, the tetanic contractile tension in unloaded soleus recovered to 94% P(0) in S10P group and 95% P(0) in L10P. After moderate fatigue, the tetanic contractile tension in unloaded soleus recovered to 92% P(0) in S50P and 84% P(0) in L50P at the 20th minute. There were significant decreases in all of the fatigue groups as compared with the control groups. These results suggest that both slight and moderate fatigue inhibit the myofibrils and sarcoplasmic reticulum Ca(2+) release channels in 1-week unloaded soleus, so the recovery rate after tetanic fatigue is slower than that in the control group.
Animals ; Caffeine ; pharmacology ; Calcium ; metabolism ; Hindlimb Suspension ; Male ; Muscle Fatigue ; physiology ; Muscle, Skeletal ; pathology ; physiopathology ; Muscular Atrophy ; physiopathology ; Rats ; Rats, Sprague-Dawley ; Ruthenium Red ; pharmacology ; Ryanodine Receptor Calcium Release Channel ; physiology

OBJECTIVEMuscle contraction may prompt glucose uptake through non-insulin-dependent ways, and it may be due to the enhanced activation of key proteins known to regulate glucose metabolism, like p38 and Akt. Our experiment focused on the impact of different contraction modes on the phosphorylation of the molecules, thus to explore effective ways to lower blood glucose.

METHODSIsolated muscle strips perfusion technique and Western blot analysis were employed to investigate the influence of different modes of contraction on the activation of the molecules.

RESULTSMuscle contraction led to an increase in p38 phosphorylation, with the greatest effect observed after 5 minutes of 10% DC (duty cycle) contraction and 5 minutes of 1% DC contraction. However, phosphorylation of Akt were not altered by the two contraction modes.

CONCLUSIONThe level of phosphorylation of p38 was higher at the optimal contraction modes, but these modes could not increase the level of phosphorlation of Akt.

Animals ; Glucose ; metabolism ; In Vitro Techniques ; Male ; Muscle Contraction ; physiology ; Muscle, Skeletal ; physiology ; Phosphatidylinositol 3-Kinases ; metabolism ; Phosphorylation ; Physical Conditioning, Animal ; physiology ; Proto-Oncogene Proteins c-akt ; metabolism ; Rats ; Rats, Sprague-Dawley ; p38 Mitogen-Activated Protein Kinases ; metabolism