Minocycline inhibits formalin-induced inflammatory pain and the underlying mechanism / 北京大学学报(医学版)

OBJECTIVE@#To unravel the underlying mechanism of minocycline in formalin-induced inflammatory pain, and to investigate the effects of minocycline on synaptic transmission in substantia gela-tinosa (SG) neurons of rat spinal dorsal horn.@*METHODS@#Behavioral and immunohistochemistry experiments: 30 male Sprague-Dawley (SD) rats (3-5 weeks old) were randomly assigned to control (n=8 rats), model (n=8 rats), saline treatment model (n=6 rats) and minocycline treatment model (n=8 rats) groups. The control group was subcutaneously injected with normal saline on the right hindpaws. Acute inflammatory pain model was established by injecting 5% (volume fraction) formalin into the right hindpaws. The rats in the latter two groups received intraperitoneal injection of saline and minocycline 1 h before the formalin injection, respectively. The time of licking and lifting was recorded every 5 min within 1 h after the subcutaneous injection of normal saline or formalin for all the groups, which was continuously recorded for 1 h. One hour after the pain behavioral recording, the spinal cord tissue was removed following transcardial perfusion of 4% paraformaldehyde. The expression of c-Fos protein in spinal dorsal horn was observed by immunohistochemistry. Electrophysiological experiment: In vitro whole-cell patch-clamp recordings were performed in spinal cord parasagittal slices obtained from 26 male SD rats (3-5 weeks old). Two to five neurons were randomly selected from each rat for patch-clamp recording. the effects of minocycline, fluorocitrate and doxycycline on spontaneous excitatory postsynaptic currents (sEPSCs) or spontaneous inhibitory postsynaptic currents (sIPSCs) of SG neurons were investigated.@*RESULTS@#Compared with the control group, both the licking and lifting time and the expression of c-Fos protein in ipsilateral spinal dorsal horn of the model group were significantly increased. Intraperitoneal injection of minocycline largely attenuated the second phase of formalin-induced pain responses (t=2.957, P<0.05). Moreover, c-Fos protein expression was also dramatically reduced in both the superficial lamina (I-II) and deep lamina (III-IV) of spinal dorsal horn (tI-II=3.912, tIII-IV=2.630, P<0.05). On the other side, bath application of minocycline significantly increased the sIPSCs frequency to 220%±10% (P<0.05) of the control but did not affect the frequency (100%±1%, t=0.112, P=0.951) and amplitude (98%±1%, t=0.273, P=0.167) of sEPSCs and the amplitude (105%±3%, t=0.568, P=0.058) of sIPSCs. However, fluorocitrate and doxycycline had no effect on the frequency [(99%±1%, t=0.366, P=0.099); (102%±1%, t=0.184, P=0.146), respectively] and amplitude [(98%±1%, t=0.208, P=0.253); (99%±1%, t=0.129, P=0.552), respectively] of sIPSCs.@*CONCLUSION@#Minocycline can inhibit formalin-induced inflammatory pain and the expression of c-Fos protein in spinal dorsal horn. These effects are probably due to its enhancement in inhibitory synaptic transmission of SG neurons but not its effect on microglial activation or antibiotic action.

Highly expressed MT-ND3 positively associated with histological severity of hepatic steatosis.

Hepatic steatosis is the accumulation of an excess amount of triglycerides and other fats inside liver cells resulting from abnormal hepatic lipid metabolism. Mitochondrial structural and molecular defects are involved in the progression of hepatic steatosis pathogenesis. Hepatic methylation and transcriptional activity of the mitochondrial-encoded NADH dehydrogenase (MT-ND) play a critical role in the progression of non-alcoholic fatty liver disease (NAFLD). However, the expression of MT-ND3 in hepatic steatosis has not been extensively studied. In this study, liver specimens were collected from different patients, and were subjected to immunohistochemistry. Primary hepatocytes were treated with oxidative stress, hypoxia, and lipotoxicity to investigate the respective roles of these factors on MT-ND3 expression and cell apoptosis by western blotting and flow cytometry, respectively. We found that increased MT-ND3 expression in human hepatic steatosis was positively associated with histological severity of hepatic steatosis. Hypoxia, H2O2 , and saturated fatty acid treatment induced cell apoptosis mediated by mitochondria. These three factors all had effects on MT-ND3 expression in cultured hepatocytes. Taken together, MT-ND3 may play important roles in hepatic steatosis progress. Hypoxia, oxidative stress, and lipotoxicity could all influence expression of MT-ND3 and thus may play a role in the progression of hepatic steatosis.

Baicalein, a natural product, selectively activating AMPKα(2) and ameliorates metabolic disorder in diet-induced mice.

The aim of the present study was to determine the effect of baicalein on metabolic syndrome induced by a high-fat diet in mice. The mice developed obesity, dyslipidemia, fatty liver, diabetes and insulin resistance. These disorders were effectively normalized in baicalein-treated mice. Further investigation revealed that the inhibitory effect on inflammation and insulin resistance was mediated by inhibition of the MAPKs pathway and activation of the IRS1/PI3K/Akt pathway. The lipid-lowering effect was attributed to the blocking of synthesis way mediated by SERBP-1c, PPARγ and the increased fatty acid oxidation. All of these effects depended on AMPKα activation. These results were confirmed in the primary hepatocytes from wild type and AMPKα(2)(-/-) mice. However, the IRS-1/PI3K/AKT pathway showed no change, which may be due to the time of stimulation and concentration. Thus, these data suggested that baicalein protects mice from metabolic syndrome through an AMPKα(2)-dependent mechanism involving multiple intracellular signaling pathways.

[Applied anatomy of the inguinal region and laparoscopic inguinal hernia repair].

OBJECTIVE: To investigate the regional anatomy of the inguinal region and abdominal ring and provide accurate anatomic basis for the clinical application of total peritoneum intraperitoneal onlay mesh (TPIPOM). METHODS: The structures of the inguinal region and those surrounding the abdominal ring of 18 cadavers (11 males and 7 females, 36 sides) were dissected to measure the lengths from the nerves and vessels to the corresponding anatomical landmarks. RESULTS: The average distances from the point where the iliohypogastric nerve (IHN) ran through the obliquus internus abdominis to anterosuperior iliac spine and from the point where the IHN ran through the aponeurosis of the external oblique muscle of the abdomen to the superior margin of the symphysis pubica were 4.10±0.89 cm and 5.02±1.46 cm, respectively. The average distances from the point where the ilioinguinal nerve (IGN) ran through the obliquus internus abdominis to the anterosuperior iliac spine and from the point where IGN ran through the aponeurosis of the external oblique muscle of the abdomen to the superior surface of the tuberculum pubicum were 3.09±0.81 cm and 3.84±0.89 cm, respectively. We established the regional anatomy model of the structures surrounding the abdominal ring. CONCLUSION: The quantitative measurement of important structures of the inguinal region and establishment of the regional anatomy model of the surrounding structures of the abdominal ring can provide a valuable reference to reduce intraoperative and postoperative complications of TPIPOM.

[Immunological influence of iodine-125 implantation in patients with hepatocellular carcinoma resection].

OBJECTIVE: To investigate the effect of iodine-125 implantation on immune cell subsets and cytokine production in patients undergoing hepatocellular carcinoma (HCC) resection. METHODS: Sixty-eight patients with resectable HCC were randomly divided into intrahepatic iodine-125 embedding group and control group. The percentages of T lymphocyte phenotypes (CD3(+), CD4(+), CD8(+)), NK cells, and the plasma concentrations of IL-4, IL-10, IL-12 and IFN-gamma of the patients were determined with flow cytometry and ELISA, respectively. RESULTS: In the control group, the postoperative CD3(+) and CD4(+) immunocytes were (39.38-/+6.98)% and (24.34-/+3.18)%, significantly lower than the preoperative levels [(62.58-/+8.67)% and (30.63-/+4.19)%, respectively, P<0.05)]. The postoperative concentrations of IL-4 and IL-10 were (29.83-/+7.99) and (87.54-/+2.89) ng/L, significantly higher than the preoperative levels (10.35-/+8.76 and 64.25-/+2.54 ng/L, respectively, P<0.05). In the treatment group, the percentages of the immunocytes and cytokine concentrations underwent no significant changes after the operation, but postoperative IL-12 (89.46-/+11.43 ng/L) and IFN-gamma (47.78-/+5.45 ng/L) levels were significantly higher than the preoperative levels (36.13-/+9.16 and 7.14-/+2.17 ng/L, respectively, P<0.05). Significant differences were found between the two groups in the postoperative CD3(+) and CD4(+) immunocytes and IL-4, IL-10, IL-12 and IFN-gamma levels. CONCLUSION: Iodine-125 implantation can strongly stimulates the anti-tumor immune response in HCC patients by increasing CD3(+) and CD4(+) immunocytes and promoting Th2/Th1 deviation.