Objective To observe the protein expression of c-Jun amino-terminal kinase (JNK) and extracellular signal-regulated kinase (ERK) in normal skin and keloid and to explore their influences on the formation of kloid. Methods Keloid tissues and normal skin tissues were collected from 16 keloid resection patients (experimental group) and 10 voluntary plastic surgery patients (control group). In the experimental group, the keloid formation time ranged from 8 months to 10 years; the keloid tissues were collected from the chest in 6 cases, the ear lobe in 4 cases, the perineum in 2 cases, the shoulder in 3 cases, and the abdomen in 1 case; and all keloid tissues were confirmed by pathological examination. In the control group, normal skin tissues were collected from the abdomen in 4 cases, the thighs in 3 cases, the shoulder in 2 cases, and the back in 1 case. Two-step l ine of Envision immunohistochemical staining was performed to observe the expressions of nonphosphorylated and phosphorylated JNK and ERK; Image Pro Plus 4.5 image analysis system was used to measure the integrated absorbance (IA) and to observe the positive staining strength. Results The immunohistochemical staining showed that no obvious expressions of phosphorylated and non-phosphorylated ERK, JNK were observed in the fibroblasts of the control group, and the expressions of phosphorylated JNK and ERK proteins were significantly higher in the experimental group than in the control group (P lt; 0.05). There was no significant difference in the expressions of non-phosphorylated JNK and ERK proteins between 2 groups (P gt; 0.05). Conclusion Activation of ERK and JNK pathways might be involved in formation of keloid.
Objective To explore the change tendency of hypoxia-inducible factor-1α (HIF-1α) and extracellular signal-regulated kinase 1/2 (ERK1/2) in fetal rat cerebral cortex neurons cultured in vitro after hypoxia-ischemia reperfusion andto investigate their mutual relationship. Methods Cortical neurons obtained from cerebral cortex of 15 pregnant SD rats at16-18 days of gestation underwent primary culture. The primary neurons 5 days after culture were adopted to establ ish model of oxygen and glucose deprivation (OGD). The experiment was divided into 4 groups: the experimental group 1, culture medium was changed to neuron complete medium containing glucose after the preparation of OGD model to form reperfusion, and the neurons were observed 0, 2, 4, 8, 12 and 24 hours after reperfusion; the control group 1, the neurons were treated with normal medium; the experimental group 2, the neurons were pretreated with U0126 followed by the preparation of OGD model, and the neurons were observed 4 and 8 hours after reperfusion; the control group 2, the neurons were pretreated with DMSO, and other treatments were the same as the experimental group 2. Expressions of HIF-1α, VEGF protein, ERK1/2 and p-ERK1/2 were detected by Western blot. Expression and distribution of p-ERK1/2 and HIF-1α protein were detected by SABC immunocytochemistry method. Results Compl icated synaptic connections between cortical neurons processes were observed 5 days after culture. The expression of HIF-1α and VEGF were increased gradually, peaked at 8 hours, and decreased gradually after 12 hours in the experimental group 1, and there were significant differences between the experimental group 1 and the control group 1 (P lt; 0.05). There was no significant difference between the experimental group 1 and the control group 1 in terms of ERK1/2 protein expression (P gt; 0.05). The p-ERK1/2 protein expression in the experimental group 1 started to increase at 2 hours peaked at 4 hours, and started to decrease at 8 hours, showing significant differences compared with the control group 1 (P lt; 0.01). In the experimental group 2, the p-ERK1/2 protein decreased, and HIF-1αand VEGF protein expression subsequentlydecreased, showing significant differences compared with the control group 2 (P lt; 0.05). There was no significant difference between the experimental group 2 and the control group 2 in terms of ERK1/2 protein expression at each time point (P gt; 0.05). Immunocytochemistry staining showed that p-ERK1/2 and HIF-1α expression decreased, and the yellow-brown staining of the neurons was reduced. Conclusion Expressions of HIF-1α and its target-gene VEGF protein in the cortex neurons after OGD reperfusion are time-dependent. Their expressions decrease when ERK1/2 signal ing pathway is inhibited, indicating the pathway plays an important role in the regulation of HIF-1α and VEGF induced by OGD of cortical neurons
Objective To investigate the possible signaling mechanisms by which recombinant human plateletderived growth factor (rhPDGF) accelerated healingof cutaneous wound in diabetic rats. Methods Four full-thickness skin woundswere incised in the back of 26 male Wistar diabetic rats. The wounded rats were divided into 3 groups (7 or 8 rats each group). One group without treatmentwas used as a control, and the other 2 groups were treated with rhPDGF at a dose of 7.0 μg/cm2 wound or vehicle (DMSO/09% NaCl, vol/vol 1∶1) from 1 to14 days. The wound healing was evaluated by the measurements of the wound volume and area. Immunofluorescent and immunohistochemical staining were used to examine the phosphorylation of extracellular signalregulated kinase 1/2 (ERK1/2) andthe expression of proliferative cell nuclear antigen (PCNA), respectively. Results Granulation tissue appeared in the bed of wound after injury. The number of blood capillary buds and fibroblasts was greater in the rhPDGF-treated group than that in the other 2 groups. A lot of inflammatory cells infiltration and collagen deposition were observed in the wound. The wound-volume in the rhPDGF-treated group was smaller than that in control group (Plt;0.05). The reepithelialization rate in rhPDGF-treated group was higher than that inthe other 2 groups at 7 days after injury (Plt;0.05). The expression of PCNA in reparative cells was higher in rhPDGF-treated group than in control group or vehicle-treated group at 3,7 days after injury(Plt;0.05). The phosphorylation of ERK1/2 was ber in rhPDGF-treated group than that in control group or vehicle group at 7 and 14 days after injury(Plt;0.05). Conclusion These results suggest that rhPDGF accelerates wound healing and improves healing quality by increasingthe phosphorylation of ERK1/2.