Electroacupuncture alleviates ciliary muscle cell apoptosis in lens-induced myopic guinea pigs through inhibiting the mitochondrial signaling pathway

AIM:To investigate the effect of electroacupuncture(EA)on the mitochondria-dependent apoptotic signaling pathway in the ciliary muscle of guinea pigs with negative lensinduced myopia(LIM).METHODS:Guinea pigs were randomly divided into normal control(NC)group,LIM group,LIM+SHAM acupoint(LIM+SHAM)group,and LIM+EA group.Animals in the NC group received no intervention,while those in other three groups were covered with-6.0 diopter(D)lenses on right eyes.Meanwhile,animals in the LIM+EA group received EA at Hegu(LI4)combined with Taiyang(EX-HN5)acupoints,while those in the LIM+SHAM group were treated at sham points.After treatments for 1,2,and 4wk,morphological changes in ciliary muscles were observed with hematoxylin and eosin(H&E)staining and nick end labeling(TUNEL),and the expression of the mitochondrial apoptotic signaling pathway-related molecules in ciliary muscles was measured by real-time quantitative polymerase chain reaction(qPCR)and Western blot.Additionally,the adenosine triphosphate(ATP)contents were also determined in ciliary muscles.RESULTS:Axial length increased significantly in the LIM and LIM+SHAM groups and decreased in the LIM+EA group.The ciliary muscle fibers were broken and destroyed in both LIM and LIM+SHAM groups,whereas those in the LIM+EA group improved significantly.TUNEL assay showed the number of apoptotic cells increased in the LIM and LIM+SHAM groups,whereas reduced in the LIM+EA group.ATP contents showed a significant decrease in the LIM and LIM+SHAM groups,whereas increased after EA treatment.Compared with the NC group,the dynamin-related protein 1(DRP1),Caspase3,and apoptotic protease activator 1(APAF1)levels were significantly increased in the LIM group and decreased in the LIM+EA group.CONCLUSION:The results provide evidence of EA inhibiting the development of myopia by regulating the mitochondrial apoptotic signaling pathway.

Human ciliary muscle cell responses to kinins:Activation of ERK1/2 and pro-matrix metalloproteinases secretion

AIM To study activation of extracellular signal-regulated kinase-1/2(ERK1/2) and pro-matrix metalloproteinases(pro-MMPs) secretion from isolated primary human ciliary muscle(h-CM) cells in response to bradykinin(BK) and other agonists. METHODS Serum-starved h-CM cells were challenged with vehicle, BK agonists or antagonists. Cell lysates were evaluated for phosphorylated ERK1/2 using homogeneous timeresolved fluorescence technology based on a sandwich immunoassay. Rabbit polyclonal anti-pro-MMP antibodies were used to measure pro-MMPs using immunoblot analysis.RESULTS A 10 min incubation time using 5 × 104 h-CM cells/well was optimum condition for studying stimulation of ERK1/2 phosphorylation. BK(100 nmol/L) caused a 1.86 ± 0.26 fold(n = 3) increase in ERK1/2 phosphorylation above baseline. BK analogs, Met-Lys-BK and RMP-7(100 nmol/L), also stimulated ERK1/2 phosphorylation by 1.57 ± 0.04 and 1.55 ± 0.09 fold, respectively. However, DesArg9-Bradykinin, a B1 receptor-selective agonist(0.1-1 μmol/L), was essentially inactive. HOE-140 or WIN-64338(B2-antagonists) appreciably blocked phosphorylation of ERK1/2 induced by various BK agonists. Pre-treatmentof cells with a prostaglandin(PG) synthase inhibitor(bromfenac; 1 μmol/L) failed to alter kinin-induced ERK1/2 activation. BK and a non-peptide BK agonist(FR-190997)(10 nmol/L-1 μmol/L) also enhanced pro-MMPs secretion(pro-MMP-1 > pro-MMP-3 > pro-MMP-2; 1.45-1.75-fold over baseline) from h-CM cells. CONCLUSION These collective data suggest that B2 kinin receptors initiate signaling in h-CM cells by a relatively rapid mechanism(within minutes) involving ERK1/2 activation which in turn regulates MMPs production(within hours). The latter process does not involve PGs.