Diabetes and high-glucose could upregulate the expression of receptor for activated C kinase 1 in retina

Figure 1 Blood glucose levels and body weight of rats following intraperitoneal injection of streptozotocin (65 mg/kg) (pH 4. 5) in citrate buffer. A: Blood glucose level; B: Body weight. The results are presented as the mean ± SD. ^aP < 0.05 vs control group (n = 6 in each group). NC: Normal control; DM: Diabetes mellitus.

Figure 2 Retinal hematoxylin and eosin staining (magnification, 400) and retinal pigment epithelium cell counts were performed in normal and diabetic rats. A: The hematoxylin and eosin staining of rat retina; B: The quantification of retinal pigment epithelium cells. The results are expressed as the mean ± SD. ^aP < 0.05 vs control group. NC: Normal control; DM: Diabetes mellitus.

Figure 3 Aberrant expression of receptor for activated C kinase 1 and protein kinase C-ε in the retina of diabetic rats. A and B: The protein levels of receptor for activated C kinase 1 and protein kinase C-ε in the retinas of N and DM rats were measured at 8 wk following streptozotocin injection; C and D: The protein levels of receptor for activated C kinase 1 and protein kinase C-ε in the retinas of N and DM rats were measured at 10 wk following streptozotocin injection. The results are expressed as the mean ± SD. ^bP < 0.01 vs control group. N: Normal control; DM: Diabetes mellitus; 8 W: 8 wk; 10W: 10 wk; RACK1: Receptor for activated C kinase 1; PKC- ε: Protein kinase C-ε.

Figure 4 High glucose combined with hypoxia up-regulated transcription and increased protein levels of receptor for activated C kinase 1 and protein kinase C-ε in adult retinal pigment epithelium cell line-19 cells. A and B: The protein levels of receptor for activated C kinase 1 (RACK1) and protein kinase C-ε (PKC- ε) in the adult retinal pigment epithelium cell line-19 (ARPE-19) cells of normal control and high glucose combined with hypoxia; C: The ratio of mRNA of RACK1 and PKC- ε in ARPE-19 cells. The results are expressed as the mean ± SD. ^aP < 0.05 vs control group. ^bP < 0.01 vs control group. NC: Normal control; Hg + Hypo: High glucose combined with hypoxia; RACK1: Receptor for activated C kinase 1; PKC- ε: Protein kinase C-ε.

Figure 5 Silencing of receptor for activated C kinase 1 in adult retinal pigment epithelium cell line-19 cells under high glucose combined with hypoxia down-regulated protein kinase C-ε. A and B: The mRNA levels of receptor for activated C kinase 1 (RACK1) and protein kinase C-ε (PKC- ε) in the normal control, high glucose combined with hypoxia, non-silent siRNA, and silenced RACK1 siRNA groups; C-E: The protein levels of RACK1 and PKC-ε in adult retinal pigment epithelium cell line-19 cells of each group. The results are expressed as the mean ± SD. ^aP < 0.05 vs normal control. ^bP < 0.05 vs non-silent siRNA-normal control. NC: Normal control; Hg + Hypo: High glucose combined with hypoxia; siRNA-NC: Non-silent siRNA; siRNA-RACK1: Silenced RACK1 siRNA; RACK1: Receptor for activated C kinase 1; PKC- ε: Protein kinase C-ε.

Figure 6 Silencing receptor for activated C kinase 1 inhibits reactive oxygen species elevation, apoptosis, and cell leakage in adult retinal pigment epithelium cell line-19 cell monolayers under high-glucose hypoxia. A and B: The apoptosis rate of adult retinal pigment epithelium cell line-19 cells was measured in the normal control (NC), high glucose combined with hypoxia, non-silent siRNA-NC, and silenced receptor for activated protein kinase C1 siRNA groups under high glucose hypoxia; C: The FITC-dextran leakage level in the cells of each group, used to analyze the permeability between cell levels in monolayers; D: The reactive oxygen species (ROS) production level of ROS detection kit in the cells of each group. The results are expressed as the mean ± SD. ^aP < 0.05 vs normal control. ^bP < 0.05 vs siRNA-normal control. NC: Normal control; Hg + Hypo: High glucose combined with hypoxia; siRNA-NC: Non-silent siRNA; siRNA-RACK1: Silenced RACK1 siRNA; ROS: Reactive oxygen species; RACK1: Receptor for activated C kinase 1.