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Expression of calpains in the kanamycin-damaged guinea pig cochlea
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Abstracts / Cell Biology International 32 (2008) S1eS67
death is significantly positively correlated with differential changes of local blood supply during the reperfusion following AHIOP.
EXPRESSION OF CALPAINS IN THE KANAMYCINDAMAGED GUINEA PIG COCHLEA Ai Mei Wang, De Ju Ma, Dong yan Bao, Zhi Jie Chang Department of Physiology, Liaoning Medical University, Jinzhou, China Apoptosis may play an important role in the mechanism of aminoglycoside ototoxicity. Calpains are regarded to be essential for mediation and promotion of cell death in the inner ear. Thus in this study we investigated the expression of calpains in the kanamycin-poisoned guinea pig cochlea, and to explore the role of calpains on the parmanent hearing loss induced by kanamycin. Immunohistochemistry and imaging analysis technique were used to detect the expression and localization of m-calpain and m-calpain, and auditory thresholds were measured by evoked auditory brainstem response (ABR). We demonstrated that m-calpain and m-calpain were co-localized in hair cells, in cells of stria vascularis and in spiral ganglion cells. Lower expression was seen in saline-injected control cochlear tissue. After treatment with kanamycin for 14 days, immunostaining for m-calpain and m-calpain became more intense, and auditory threshold shifts were significantly elevated about 30 dB. These results suggest that calpain may be responsible for apoptosis induced by aminoglycoside. This indicates that calpain inhibitor may be of potential therapeutic value in protecting from aminoglycoside-induced hearing loss.
ROLE OF BRAIN ANGIOTENSIN AT1 RECEPTOR IN CARBACHOL-INDUCED NATRIURESIS AND EXPRESSION OF THYROSINE HYDROXYLASE IN THE ROSTRAL VENTROLATERAL MEDULLA Min Wang 1,2, Chun Ling Jiang 1, Man Li Xia 1, Chun Yan Wang 3, Qi YingYao 2 1 Department of Physiology, Jiaxing University, School of Medicine, Jiaxing, China 2 Department of Physiology, Dalian Medical University, Dalian, China 3 Department of Renal Medicine, Neimenggu Hospital, Neimeng, China Central administration of angiotensin II type 1 (AT1) receptor antagonist losartan effectively inhibited the increase in blood pressure and drinking response induced by cholinergic agonist carbachol. However, whether the angiotensin AT1 receptor is related to the natriuresis induced by brain cholinergic stimuli is still unclear. The purpose of this study was to investigate the role of brain angiotensin AT1 receptor in the carbachol-induced natriuresis and expression of thyrosine hydroxylase (TH) in the rostral ventrolateral medulla (RVLM) in Sprague Dawley (SD) rats. The results showed that after intracerebroventricular (ICV) injection of carbachol (0.5 mg), the urinary sodium excretion increased at 20 min, reaching the peak [(0.548 0.049) mmol/min$100g] at 40 min. Immunohistochemistry showed that carbachol induced an increase of thyrosine hydroxylase-immunoreactivity (TH-IR) in the RVLM. After pretreatment with 20 mg of losartan, the urinary sodium excretion reduced to (0.249 0.067) mmol/min$100g, and TH-IR in the RVLM induced by carbachol was also reduced. The results suggest that brain AT1 receptor was involved in carbachol-induced natriuresis and the increase in activity of adrenergic neurons in the RVLM. Consequently, we provided the new evidence that brain angiotensinergic pathway and adrenergic pathway contributed to renal changes in the natriuresis to brain cholinergic stimuli and thus played an important role in the regulation of fluid homeostatic.
ROLE OF GLUTAMATE AND ITS NMDAR IN HYPEROXIAINDUCED LUNG INJURY Ming Jie Wang 1, Zi Qiang Luo 2, Shuang Liu 1,3, Xiao Dan Deng 1, Fu Rong Huang 1, Li Hong Shang 1, Chang E Jian 1, Shao Jie Yue* 1 1 Department of Pediatrics, Xiangya Hospital of Central South University, Changsha, China
2 Department of Physiology, Xiangya Medical College, Central South University, Changsha, China 3 Department of Emergency, Capital institute of Pediatrics, Beijing, China
Previous study in our laboratory showed that NMDA receptor antagonist MK801 could decrease the hyperoxia lung damage. The purpose of the study was to demonstrate the role of intrinsic Glu and NR2D in hyperoxia-induced lung injury. 22-day gestation full term rats in 12 hours after birth were randomly marked with a different number and assigned to four groups: air control group, air+MK-801 group, hyperoxia group and hyperoxia+MK-801 group. The content of LDH was significantly higher after having 1d exposure. After 3 days, content of protein and LDH, the counts of inflammatory cell, and W/D were much higher than air group. After 7 days, LDH, protein, W/D were much higher than air group. Our data show that MK-801 had no influence on the content of LDH in BALF after 1d exposure, and also no effect on the content of protein after 3 days. The hyperoxia+MK-801 group showed less of W/D and LDH than the hyperoxia-group after 3 days and 7 days. The content of Glu was significantly higher after having 1d exposure. After having 3 days exposure, NR2D mRNA expressions were much higher than air group (P<0.05). After having 7 days of exposure, NR2D mRNA expressions were much higher than the 1 d and 3 days, and also higher than air group. The content of Glu in BALF had a dramatic decrease; it was not lower than 3 days, but lower than air group. In conclusion, hyperoxia could induce the release of intrinsic Glu in lung and enhance the expression of NMDA receptor. NMDA receptor antagonist MK-801 can alleviated hyperoxia-induced lung injury in neonatal rats in 3 days - 7 days hyoeroxia exposured time. Glu and NMDA receptors may play an excitotoxicity role in the pathogenesis of hyperoxia-induced lung injury.
3, 4, 5, 6-TETRAHYDROXYXANTHONE PROTECTS AGAINST HYPOXIA/ REOXYGENATION-INDUCED APOPTOSIS OF PC12 CELLS: ROLE OF THE DDAH/ADMA PATHWAY Shan Wang 2, De Jian Jiang 1, Jun Lin Jiang 1, Ke Long Huang 2, Yuan Jian Li* 1 1 Department of Pharmacology, School of Pharmaceutical Sciences 2 Department of Pharmaceutical Engineering, College of Chemistry and Chemical Engineering, Central South University, Changsha, 410078, China Our previous studies showed that 3,4,5,6-tetrahydroxyxanthone (Xan), a synthesized polyphenolic compound, protected against myocardial ischemia/ reperfusion (I/R) injury. Endogenous nitric oxide synthase inhibitor asymmetric dimethylarginine (ADMA), which is hydrolyzed by dimethylarginine dimethylaminohydrolase (DDAH), was reported to induce apoptotic death in various kinds of cells. In the present study, we observed the inhibitory effect of Xan on hypoxia/reoxygenation (H/R)-induced apoptosis in PC12 (pheochromocytoma) cells and investigated the relationship between anti-apoptotic action of Xan and the DDAH/ADMA pathway. Three-hour hypoxia (1 % O2) and consequent 24-hour reoxygenation significantly increased the apoptotic death of PC12 cells as evidenced by increases in Hochest stainingpositive cell number, concomitantly with increasing intracellular reactive oxygen species (ROS) production and caspase-3 activity, which was attenuated by pretreatment with Xan (3 e 30 mM) and caspase-3 inhibitor DEVD-CHO as well as antioxidant PDTC. Also, the decrease in DDAH activity and the increase in ADMA level were also observed after H/R treatment. Furthermore, incubation with exogenous ADMA (1 e 10 mM) could concentration-dependently increase caspase-3 activity and induce the apoptosis of PC12 cells. Pretreatment with Xan could markedly attenuate the decrease in DDAH activity and the increase in ADMA level and inhibit ADMAinduced caspase-3 activation and apoptosis of PC12 cells. In summary, the present data suggest that Xan protects against H/R-induced apoptosis via inhibiting caspase-3-dependent apoptotic signaling pathway, which may be related to improving the DDAH/ADMA pathway by reduction of oxidative stress.
Abstracts / Cell Biology International 32 (2008) S1eS67
death is significantly positively correlated with differential changes of local blood supply during the reperfusion following AHIOP.
EXPRESSION OF CALPAINS IN THE KANAMYCINDAMAGED GUINEA PIG COCHLEA Ai Mei Wang, De Ju Ma, Dong yan Bao, Zhi Jie Chang Department of Physiology, Liaoning Medical University, Jinzhou, China Apoptosis may play an important role in the mechanism of aminoglycoside ototoxicity. Calpains are regarded to be essential for mediation and promotion of cell death in the inner ear. Thus in this study we investigated the expression of calpains in the kanamycin-poisoned guinea pig cochlea, and to explore the role of calpains on the parmanent hearing loss induced by kanamycin. Immunohistochemistry and imaging analysis technique were used to detect the expression and localization of m-calpain and m-calpain, and auditory thresholds were measured by evoked auditory brainstem response (ABR). We demonstrated that m-calpain and m-calpain were co-localized in hair cells, in cells of stria vascularis and in spiral ganglion cells. Lower expression was seen in saline-injected control cochlear tissue. After treatment with kanamycin for 14 days, immunostaining for m-calpain and m-calpain became more intense, and auditory threshold shifts were significantly elevated about 30 dB. These results suggest that calpain may be responsible for apoptosis induced by aminoglycoside. This indicates that calpain inhibitor may be of potential therapeutic value in protecting from aminoglycoside-induced hearing loss.
ROLE OF BRAIN ANGIOTENSIN AT1 RECEPTOR IN CARBACHOL-INDUCED NATRIURESIS AND EXPRESSION OF THYROSINE HYDROXYLASE IN THE ROSTRAL VENTROLATERAL MEDULLA Min Wang 1,2, Chun Ling Jiang 1, Man Li Xia 1, Chun Yan Wang 3, Qi YingYao 2 1 Department of Physiology, Jiaxing University, School of Medicine, Jiaxing, China 2 Department of Physiology, Dalian Medical University, Dalian, China 3 Department of Renal Medicine, Neimenggu Hospital, Neimeng, China Central administration of angiotensin II type 1 (AT1) receptor antagonist losartan effectively inhibited the increase in blood pressure and drinking response induced by cholinergic agonist carbachol. However, whether the angiotensin AT1 receptor is related to the natriuresis induced by brain cholinergic stimuli is still unclear. The purpose of this study was to investigate the role of brain angiotensin AT1 receptor in the carbachol-induced natriuresis and expression of thyrosine hydroxylase (TH) in the rostral ventrolateral medulla (RVLM) in Sprague Dawley (SD) rats. The results showed that after intracerebroventricular (ICV) injection of carbachol (0.5 mg), the urinary sodium excretion increased at 20 min, reaching the peak [(0.548 0.049) mmol/min$100g] at 40 min. Immunohistochemistry showed that carbachol induced an increase of thyrosine hydroxylase-immunoreactivity (TH-IR) in the RVLM. After pretreatment with 20 mg of losartan, the urinary sodium excretion reduced to (0.249 0.067) mmol/min$100g, and TH-IR in the RVLM induced by carbachol was also reduced. The results suggest that brain AT1 receptor was involved in carbachol-induced natriuresis and the increase in activity of adrenergic neurons in the RVLM. Consequently, we provided the new evidence that brain angiotensinergic pathway and adrenergic pathway contributed to renal changes in the natriuresis to brain cholinergic stimuli and thus played an important role in the regulation of fluid homeostatic.
ROLE OF GLUTAMATE AND ITS NMDAR IN HYPEROXIAINDUCED LUNG INJURY Ming Jie Wang 1, Zi Qiang Luo 2, Shuang Liu 1,3, Xiao Dan Deng 1, Fu Rong Huang 1, Li Hong Shang 1, Chang E Jian 1, Shao Jie Yue* 1 1 Department of Pediatrics, Xiangya Hospital of Central South University, Changsha, China
2 Department of Physiology, Xiangya Medical College, Central South University, Changsha, China 3 Department of Emergency, Capital institute of Pediatrics, Beijing, China
Previous study in our laboratory showed that NMDA receptor antagonist MK801 could decrease the hyperoxia lung damage. The purpose of the study was to demonstrate the role of intrinsic Glu and NR2D in hyperoxia-induced lung injury. 22-day gestation full term rats in 12 hours after birth were randomly marked with a different number and assigned to four groups: air control group, air+MK-801 group, hyperoxia group and hyperoxia+MK-801 group. The content of LDH was significantly higher after having 1d exposure. After 3 days, content of protein and LDH, the counts of inflammatory cell, and W/D were much higher than air group. After 7 days, LDH, protein, W/D were much higher than air group. Our data show that MK-801 had no influence on the content of LDH in BALF after 1d exposure, and also no effect on the content of protein after 3 days. The hyperoxia+MK-801 group showed less of W/D and LDH than the hyperoxia-group after 3 days and 7 days. The content of Glu was significantly higher after having 1d exposure. After having 3 days exposure, NR2D mRNA expressions were much higher than air group (P<0.05). After having 7 days of exposure, NR2D mRNA expressions were much higher than the 1 d and 3 days, and also higher than air group. The content of Glu in BALF had a dramatic decrease; it was not lower than 3 days, but lower than air group. In conclusion, hyperoxia could induce the release of intrinsic Glu in lung and enhance the expression of NMDA receptor. NMDA receptor antagonist MK-801 can alleviated hyperoxia-induced lung injury in neonatal rats in 3 days - 7 days hyoeroxia exposured time. Glu and NMDA receptors may play an excitotoxicity role in the pathogenesis of hyperoxia-induced lung injury.
3, 4, 5, 6-TETRAHYDROXYXANTHONE PROTECTS AGAINST HYPOXIA/ REOXYGENATION-INDUCED APOPTOSIS OF PC12 CELLS: ROLE OF THE DDAH/ADMA PATHWAY Shan Wang 2, De Jian Jiang 1, Jun Lin Jiang 1, Ke Long Huang 2, Yuan Jian Li* 1 1 Department of Pharmacology, School of Pharmaceutical Sciences 2 Department of Pharmaceutical Engineering, College of Chemistry and Chemical Engineering, Central South University, Changsha, 410078, China Our previous studies showed that 3,4,5,6-tetrahydroxyxanthone (Xan), a synthesized polyphenolic compound, protected against myocardial ischemia/ reperfusion (I/R) injury. Endogenous nitric oxide synthase inhibitor asymmetric dimethylarginine (ADMA), which is hydrolyzed by dimethylarginine dimethylaminohydrolase (DDAH), was reported to induce apoptotic death in various kinds of cells. In the present study, we observed the inhibitory effect of Xan on hypoxia/reoxygenation (H/R)-induced apoptosis in PC12 (pheochromocytoma) cells and investigated the relationship between anti-apoptotic action of Xan and the DDAH/ADMA pathway. Three-hour hypoxia (1 % O2) and consequent 24-hour reoxygenation significantly increased the apoptotic death of PC12 cells as evidenced by increases in Hochest stainingpositive cell number, concomitantly with increasing intracellular reactive oxygen species (ROS) production and caspase-3 activity, which was attenuated by pretreatment with Xan (3 e 30 mM) and caspase-3 inhibitor DEVD-CHO as well as antioxidant PDTC. Also, the decrease in DDAH activity and the increase in ADMA level were also observed after H/R treatment. Furthermore, incubation with exogenous ADMA (1 e 10 mM) could concentration-dependently increase caspase-3 activity and induce the apoptosis of PC12 cells. Pretreatment with Xan could markedly attenuate the decrease in DDAH activity and the increase in ADMA level and inhibit ADMAinduced caspase-3 activation and apoptosis of PC12 cells. In summary, the present data suggest that Xan protects against H/R-induced apoptosis via inhibiting caspase-3-dependent apoptotic signaling pathway, which may be related to improving the DDAH/ADMA pathway by reduction of oxidative stress.