Tanshinone ⅡA activates PI3K/AKT signaling pathway to inhibit the apoptosis of mice cochlear pericytes induced by high glucose / 中华耳鼻咽喉头颈外科杂志

Objective: To investigate whether tanshinone ⅡA can protect the apoptosis of mice cochlear pericytes induced by high glucose and its specific protective mechanism, so as to provide experimental evidence for the prevention and treatment of diabetic hearing loss. Methods: C57BL/6J male mice were used to prepare type 2 diabetes model, which were divided into normal (NG) group, diabetic (DM) group, diabetic+tanshinone ⅡA (HG+tanshinone ⅡA) group and tanshinone ⅡA group. Each group had 10 animals. Primary cochlear pericytes were divided into NG group, HG group (high glucose 35 mmol/L), HG+tanshinone ⅡA (1, 3, 5 μmol/L) group, HG+Tanshinone ⅡA+LY294002 (PI3K/AKT pathway inhibitor) group, LY294002 group, tanshinone ⅡA group and DMSO group. Auditory brainstem response (ABR) was used to measure hearing threshold. Evans blue was used to detect the permeability of blood labyrinth barrier in each group. TBA methods were used to detect oxidative stress levels in various organs of mice. Morphological changes of stria vascularis were observed by hematoxylin-eosin staining (HE). Evans blue was used to detect the vascular labyrinth barrier permeability in cochlea. The expression of apoptosis protein in stria vascularis pericytes was observed by immunofluorescence. Pericytes apoptosis rate was observed by flow cytometry. DCFH-DA was combined with flow cytometry to detect intracellular ROS content, and Western blot was used to detect the expression of apoptotic proteins (Cleaved-caspase3, Bax), anti-apoptotic proteins (BCL-2) and pathway proteins (PI3K, p-PI3K, AKT, p-AKT). SPSS software was used for statistical analysis. Independent sample t test was performed, and P<0.05 was considered statistically significant. Results: Animal experiments: Tanshinone ⅡA decreased the hearing threshold of DM group [(35.0±3.5) dB SPL vs. (55.3±8.1) dB SPL] (t=4.899, P<0.01), decreased the oxidative stress level in cochlea (t=4.384, P<0.05), improved the structure disorder, atrophy of cochlea vascular lines, vacuole increased phenomenon. Tanshinone ⅡA alleviated the increased permeability of the blood labyrinth barrier [Evans blue leakage (6.84±0.27) AU vs. (8.59±0.85) AU] in the cochlea of DM mice (t=2.770, P<0.05), reversed the apoptotic protein: Caspase3 (t=4.956, P<0.01) and Bax (t=4.388, P<0.05) in cochlear vascularis. Cell experiments: Tanshinone ⅡA decreased intracellular ROS content in a concentration-dependent way (t=3.569, P<0.05; t=4.772, P<0.01; t=7.494, P<0.01); Tanshinone ⅡA decreased apoptosis rate and apoptotic protein, and increased the expression of anti-apoptotic protein, p-PI3K/PI3K and p-AKT/AKT in concentration-dependent manner (all P values<0.05); LY294002 reversed the protective effect of tanshinone ⅡA on pericytes apoptosis (all P values<0.05). Conclusion: Tanshinone ⅡA can inhibit the apoptosis of cochlear pericytes induced by high glucose by reducing oxidative stress level and activating PI3K/AKT signaling pathway under high glucose environment, thus playing a protective role in diabetic hearing loss.

Expressions of oncogenes c-fos and c-myc in skin lesion of cutaneous squamous cell carcinoma

OBJECTIVES@#To explore the expressions of c-fos and c-myc in skin lesion of cutaneous squamous cell carcinoma (CSCC).@*METHODS@#Using retrospective analysis, 73 cases of CSCC were selected from Department of Dermatology, the Second Affiliated Hospital of Xi'an Jiaotong University, which were removed between January 2000 and January 2012. It was considered as experimental group. Meanwhile, 11 cases of normal skin specimens of non tumor patients were selected as control group. The expression level of c-fos and c-myc was compared in the two groups.@*RESULTS@#The expressions of c-fos [72.60% (53/73)] and c-myc [83.56% (61/73)] in experimental group were statistically significant (P≤0.05) compared with control group (0%). Expression of c-myc protein was negatively related to differentiation of CSCC. The difference was statistically significant (χ(2)=7.26, P=0.001<0.05). While expression of c-fos protein was positively related to differentiation of CSCC, which was statistically significant (χ(2)=7.47, P=0.001 2<0.025).@*CONCLUSIONS@#The expression level of c-fos and c-myc can be used as an important indicator of CSCC differentiation, and it has closely connection with the differentiated degree, which can guide clinical prognosis.