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Objective@#The aging model of guinea pigs induced by D-galactose was set up to investigate the changes of BKCa expression and function on cochlear pericytes and their relationship with age-related hearing loss.@*Methods@#Thirty healthy 8-week-old guinea pigs were randomly divided into three groups, with 10 in each group: D-galactose aging model group, subcutaneous injection of D-galactose (500 mg/kg) daily for 6 weeks; saline control group, the same amount of saline was injected into the neck of the aging model group for 6 weeks; the blank control group, no treatment was performed. The threshold of auditory brainstem response (ABR) was detected. The content of BKCa in the perivascular cells of the guinea pig cochlear cells was detected by immunofluorescence technique. The changes of peripheral current density and BKCa current were detected by patch clamp technique. The data were analyzed by GraphPad Prism software.@*Results@#Compared with the saline group and the control group, the ABR threshold and the amplitude of the wave I were significantly decreased in the aging model group, and the difference was statistically significant (P<0.01). Compared with the control group, the expression of BKCa in the vascular pericytes of guinea pigs in the aging model group was significantly reduced (1.00±0.08 vs 0.27±0.03,the difference was statistically significant P<0.01), and the cell current density and BKCa net current value were also significantly reduced with statistically significant (P<0.01).@*Conclusions@#D-galactose can successfully induce guinea pig aging model, in which BKCa expression decreases and net current value decreases in pericytes of cochlear striavascularis, and changes in BKCa expression and function may be related to age-related hearing loss.
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Objective To investigate the effect of G protein?coupled estrogen receptor (GPER) on the diastolic function of renal interlobular artery and reduce renal ischemia?reperfusion injury in rats. Methods Female ovariectomized rats were divided into control group; ischemia?reperfusion injury (IRI) group;GPER?specific agonist (G1) intervention group;GPER?specific blocker+GPER?specific agonist (G15+G1) intervention group. Histopathological examination (HE staining), renal function test and Paller score were used to identify the success of the model and the degree of kidney damage. In vitro microvascular pressure diameter measuring instrument was used to detect the relaxation and contraction activity of renal interlobular artery in each group. Immunofluorescence technique was used to observe the expression of GPER on the renal interlobular artery. Westernblotting was used to detect the expression of GPER protein in renal interlobular artery of rats in each group. The NO content was determined by a nitrate reductase method. Results Compared with IRI group, serum BUN, Scr level and Paller score in G1 intervention group were significantly decreased (all P<0.05). The systolic rate of renal interlobar artery was significantly increased [(40.76 ± 1.57)％ vs (29.78 ± 1.87)％, P<0.05]. The results of immunofluorescence showed that GPER was expressed in renal interlobular artery smooth muscle cells and endothelial cells, and the expression of IRI group was higher than that of the control group. The expression of G15+G1 intervention group was lower than that of G1 intervention group (all P<0.05). Compared with the IRI group, the NO content in the G1 intervention group increased significantly (all P<0.05). Conclusions During renal ischemia ?reperfusion injury, GPER may regulate the systolic and diastolic activity of the renal interlobar artery by increasing the content of NO, so as to alleviate the renal ischemia?reperfusion injury.
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Objective To investigate the effect of estrogen (E2) on the connexin43 (Cx43) expression of renal interlobar arteries after renal ischemia-reperfusion injury (I/R).Methods The experiment was carried out in vivo using an SD rat I/R model.SD rats were randomly divided into normal group,sham-operation group,I/R group,and estrogen-intervention group.The functional changes of the kidney were analyzed after 24 hours of I/R;nephridial tissue section was stained by hematoxylin-eosin (HE),and Paller scores were used to evaluate the degree of kidney damage.Pressure myography was utilized to detect the vasomotor function of renal interlobar arteries.Immunofluorescence technique,qRT-PCR and Western blot were applied to determine the expression of Cx43 in renal interlobar arteries in different groups.Results Estrogen markedly decreased the levels of Cr and BUN in the serum of I/R rats (P＜0.05),and the damage of the kidney tissue could be improved noticeably.The vasomotor rate of renal interlobar arteries was (24.80 ± 3.70)％ after I/R and (41.60 ± 3.50)％ after treatment with estrogen,which was higher than that of I/R group (P＜0.05).The expression of Cx43 was lower in renal interlobar arteries of estrogen-intervention group than that in I/R group (P＜0.01).Conclusion Estrogen may reduce vascular tension and boost dilation of the artery by inhibiting Cx43 expression and GJ function.Therefore,estrogen may attenuate the damage of I/R and improve renal function.