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Objective:To explore any effect of pulsed electromagnetic field (PEMF) stimulation on intervertebral disc degeneration (IDD).Methods:Forty Sprague-Dawley rats were randomly divided into a control group, an IDD model group, a PEMF group and an observation group. An IDD model was induced in all except those in the control group. Both the PEMF and observation groups were given PEMF stimulation, while the latter was additionally injected with the A2AR agonist CGS-21680. Eight weeks after the modelling any pathological changes in the morphology of the rats′ intervertebral disc tissues were evaluated using saffron solid green staining. The expression of A2AR, cyclic adenosine phosphate (cAMP), protein kinase A (PKA), cysteine aspartate proteolytic enzyme-3 (Caspase-3), type II collagen (COL-II) and matrix metalloproteinase-3 (MMP3) in the intervertebral discs were evaluated.Results:The nucleus pulposus had shrunk, while fibrous tissues and chondrocytes had increased in the IDD model group. In the observation group the nucleus pulposus was intact and of basically normal shape. A2AR mRNA and protein levels were higher in the intervertebral disc tissue of the model group than among the control group, on average, while the levels in the observation group were significantly higher than in the other groups. In the PEMF and observation groups cAMP and PKA mRNA were significantly higher than in the IDD model group. The p38 MAPK and P-P38 MAPK levels of the IDD model group and its average P-P38 MAPK/p38 MAPK ratio were significantly higher than in the control group. In the PEMF and observation groups those indices had decreased to varying degrees, with those of the observation group significantly lower than among the model and PEMF groups on average, except for the p38 MAPK values. Caspase-3 and its mRNA were significantly higher in the model group than in the control group, on average, and those values were significantly lower in the PEMF and observation groups than in the IDD model group. The average MMP3 contents of the IDD model group had increased significantly compared with the control group, while the Col-Ⅱ level had decreased significantly. Compared with the IDD model group, the MMP3 level had decreased but Col-Ⅱ expression had increased in both the PEMF and observation groups, with significant differences between the IDD model and observation groups.Conclusions:The activation of the p38 MAPK signaling pathway by inflammatory factors to induce apoptosis is one of the important reasons for the aggravation of IDD lesions. PEMF combined with A2AR agonists can activate the A2AR/cAMP/PKA signaling pathway, inhibit p38 MAPK phosphorylation, reduce apoptosis of nucleus pulposus cells, and relieve IDD damage.
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Objective:To investigate the relationship between the number of epithelial progenitor cells(EPCs)in peripheral blood and blood parameter values in order to clarify the relationship between peripheral blood EPCs and the length of survival in elderly individuals aged 75 and beyond.Methods:Analysis was conducted on 114 individuals ≥75 years recruited from the Department of Geriatrics, Tianjin Medical University General Hospital in 2008.Clinical data were collected with December 31, 2020 as the end of the follow-up.Associations between peripheral blood EPC numbers, blood parameter values and all-cause mortality were analyzed.Results:In low and high EPC groups based on orthogonal partial least squares-discriminant analysis(OPLS-DA), D-Dimer was found to be a potential classification marker[the variable importance in projection(VIP)=4.750], out of a panel of blood tests.Blood parameters such as red blood cells(RBC), hemoglobin(HGB), hematocrit(HCT), aspartate aminotransferase(AST), gamma-glutamyl transferase(GGT), lactate dehydrogenase(LDH)and D-Dimer showed statistically significant differences between groups with different levels of EPCs(all P<0.05). Blood EPC numbers were positively correlated with RBC, HGB and HCT and negatively correlated with GGT and D-Dimer in older individuals( r=0.364, 0.343, 0.336, -0.312, -0.312, P<0.05 for all). The number of circulating EPCs had a significant positive correlation with survival time in older individuals( r=0.234, P=0.017). Based on the data of the long-term(12-years)follow-up, Logistic regression analysis suggested that the number of EPCs, age, and HCT were associated with all-cause mortality events in older individuals( OR=0.971, 1.585, 1.231, P=0.013, 0.012, 0.029). Conclusions:EPCs in the peripheral circulation may be involved in the progression of various conditions such as anemia, cardiac, hepatic and renal injury, and coagulation.The number of circulating EPCs may influence the survival of elderly individuals ≥75 years.Age and HCT may be risk factors for all-cause mortality events, whereas the number of EPCs may be a protective factor.
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Objective:To observe any regulatory effect of a pulsed electromagnetic field (PEMF) on A2A adenosine receptors (A2ARs) in the nucleus pulposus of rats with intervertebral disc degeneration (IDD), and to explore any combination with the A2ARs′ agonist-mediating ROS/PI3K/Akt signaling pathway.Methods:Fifty Sprague-Dawley rats were randomly divided into a control group, an intervertebral disc degeneration group (the model group), an A2AR agonist CGS-21680 treatment group (the agonist group), a PEMF group and a PEMF combined with CGS-21680 treatment group (the observation group). IDD was modeled in all except the rats in the control group. 100μL of CGS-21680 (100μg/kg) was injected into the L 5-6 intervertebral discs of the agonist group, while the PEMF group was given 30 minutes of PEMF intervention daily for 14 days at 1.5mT and 75Hz with a pulse width of 150μs. The observation group was injected with CGS-21680 and then given the same PEMF intervention. Primary nucleus pulposus cells from each group (50ng/mL) were cultured and the expressions of 8-OHDG, SOD, MDA and ROS were detected by immunohistochemistry, immunofluorescence or with an ELISA kit. The A2AR, PI3K, AKT and p-AKT protein levels were detected using western blotting. Results:The nucleus pulposus cells and the annulus fibrosus were obviously wrinkled, necrotic and broken in the model group but the annulus fibrosus was intact and the nucleus pulposus was almost normal in the observation group. Compared with the model group, the levels of SOD and A2AR, PI3K, p-AKT and AKT protein were higher in the agonist, PEMF and observation groups, while the expressions of MDA, ROS and 8-OHDG were weaker. The ROS level in the observation group was significantly lower than that in the agonist and PEMF groups, and the phosphorylation level of p-AKT in the observation group was significantly higher than in the agonist and PEMF groups. The average levels of SOD, A2AR, PI3K, p-AKT and AKT protein in the nucleus pulposus cells of the agonist, PEMF and observation groups were significantly higher than the IL-1β group′s average, while the average levels of MDA, ROS and 8-OHDG were significantly lower. The ROS levels in the observation group were significantly lower than in the agonist and PEMF groups, while the A2AR protein content and p-AKT phosphorylation in the observation group were significantly greater. The average Bax levels in the nucleus pulposus cells of the agonist, PEMF and observation groups were significantly lower than that in the IL-1β group, and the expression of Bcl-2 was significantly increased. There was significantly less apoptosis observed in the observation group than in the agonist and PEMF groups, while the expression of Bcl-2 was significantly higher.Conclusions:PEMF plays an anti-oxidative stress role by up-regulating A2AR activity and reducing ROS generation. Treatment with PEMF and A2AR agonist could further activate the phosphorylation of PI3K/Akt, down-regulate Bax and up-regulate Bcl-2, thus inhibiting the apoptosis of nucleus pulposus cells and alleviating the malignant progression of IDD.
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Objective To study the effect of noise pollution on serum hormone and heat shock protein-70(Hsp-70)levels in rats. Methods Forty male Wistar rats were randomly divided into control group(normal), experimental group(further divided into 35,65 and 85 dB three groups), each group 10 animals, stimulated for 30 min once a day, continually stimulated for consecutive 20 days. On the 21st day of experiment,the serum noradrenaline(NA),testosterone (T),dopamine(DA)and Hsp-70 levels were determined by enzyme-linked immunosorbent assay(ELISA). Results Compared with the control group, the body weight of experimental group(35, 65 and 85 dB groups)was reduced by 23.45%,30.13%, and 35.64%, respectively The serum T and DA levels were decreased by 9.12%, 20.06%, 37.99% and 15.49%, 8.31%, 24.88%, respectively; while the serum NA and Hsp-70 levels were increased by 35.08%, 171.52%,197.86%, and 39.34%, 195.09%, and 285.25%, respectively. All the result showed a significant difference(P<0.01). Conclusions Noise pollution can significantly affect the serum levels of hormone and heat shock protein-70 expression in rats.
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Objective To study the effect of maca extract on sport fatigue and its antioxidant effect.Methods 50 healthy male Wistar rats were randomly divided into control group (normal breeding,without swimming,equal amount of distilled water for gavage),simple swimming group (swimming,equal amount of distilled water for gavage),swimming and medicine group (divided into maca extract 4.0,8.0 and 16.0 g/(kg· bw) groups,respectively),10 rats in each group.All rats were freely swimming in the circulating water flow daily for 15 days.On the 16th day of experiment,liver tissue samples were collected.The liver lipid peroxide (LPO),superoxide dismutase (SOD),glutathione peroxidase (GSH-Px) and liver glycogen level were determined.Results When rats were administered with maca extract at the doses of 4.0,8.0,16.0 g/(kg· bw),respectively,the swimming time before sinking and the total swimming time were increased by 18.99%,64.46% and 90.69%,and 18.99%,56.23% and 94.72%,respectively,while the numbers of times of sinking were decreased by 27.44%,42.86%,64.11% (P<0.01),respectively,compared with the swimming rats without maca extract treatment.The LPO content in the liver of rats treated with maca extract 4.0,8.0,16.0 g/(kg· bw) were reduced by 31.31%,42.00% and 31.31%,respectively,while the levels of SOD,GSH-Px and liver glycogen were enhanced by 25.92%,31.82%,62.09%,12.33%,23.01%,46.36% and 17.83%,44.69%,62.99%,respectively,over those of rats without maca extract treatment.Conclusions Maca extract reduces the liver LPO level,increases liver glycogen level,improves the SOD and GSH-Px activity,therefore,plays a protective role in sport fatigue.
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Objective To study the effect of low frequency electrical stimulation on hormone levels in organs of Chinese tree shrews after death.Methods Giving Chinese tree shrews low frequency electrical stimulation.At 0 h, 3 h, 6 h, 12 h, 18 h, 24 h, 36 h and 72 h after death, the thyroid, liver, spleen were taken,and the levels of endothelin (ET), atrial natriuretic factor( ANF) , thromboxane ( TX) were determined by RIA method.At 0 h after death, midbrain ventral tegmental area ( VTA) of Chinese tree shrews was taken to detect the c-fos expression.Results After electrical stimula-tion, ET, ANF, TX levels in the cadaver organs and VTA c-fos expression of Chinese tree shrews were significantly in-creased than in the control group.The contents were decreasing with the time after death.Conclusions Low frequency e-lectrical stimulation can induce the synthesis and release of hormones in organs and c-fos expression in brain tissue of Chi-nese tree shrews.
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Objective To study the effect of low frequency electrical stimulation on blood hormone levels in differ -ent animals.Methods At 12 h, 24 h and 36 h after low frequency electrical stimulation to Chinese tree shrews , Wistar rats, and BALB/c mice, respectively, the blood noradrenaline (NA) and endothelin (ET) levels were determined by ra-dioimmunoassay ( RIA) .Results The blood NA and ET levels of electrical stimulation group were significantly higher than that in the control group (P Wistar rats >BALB/c mice.Conclusions Low frequency electrical stimulation can promote the release of noradrenaline and en -dothelin in Chinese tree shrews , Wistar rats and BALB/c mice.Reserpine can reduce the stress induced by low frequency electric stimulation to the body .