Previous studies have linked GJB2 gene and mitochondrial DNA (mtDNA) mutations to nonsyndromic hearing impairment (NSHI), but no study in China has yet investigated these mutations across all age groups. To fill the gap, this study ascertained 263 patients with NSHI between ages 2 months and 60 years and analyzed the presence of GJB2 gene and mtDNA A1555G/C1494T mutations by polymerase chain reaction (PCR) and DNA sequencing. A total of 20 types of mutations were detected for the GJB2 gene. The GJB2 gene and mtDNA A1555G/C1494T mutations were detected in 18.63 and 11.41% cases, respectively. At the first hospital visit, GJB2 gene mutations were detected in 5.97% of adult patients (>18 years) and 22.96% pediatric patients (<18 years) (χ2 =9.506, p = 0.002), and mtDNA A1555G/C1494T mutations were detected in 31.34% of adult patients and 4.59% of pediatric patients (χ2 = 35.359, p <0.001). When patients were classified by age at onset of deafness, significantly more (20.68%) pediatric patients had GJB2 gene mutations than did adult patients (0.0%) (χ2 = 4.685; p = 0.006). Mitochondrial DNA A1555G/C1494T mutations were detected in 15.38% of adult-onset and 8.86% pediatric-onset patients, respectively. Interestingly, most GJB2 gene mutation carriers experienced NSHI onset within the first year of life (65.31%), while mtDNA A1555G/C1494T mutation carriers experienced onset at any age. Therefore, GJB2 gene mutations appear to contribute to congenital deafness, while mtDNAA1555G/C1494T mutations contribute mainly to acquired deafness in Chinese individuals. Both newborn hearing screening and genetic testing are important to diagnose and treat deafness.
Jing Shen, Xiao-Ming Lei, Yang Song, Xing Tan, Qin Liu, Li-Wen Dai and Jie Yu
Objective: To observe the effects of electro-acupuncture (EA) on GRP78 and Caspase-12 gene expression in rats with ischemia- reperfusion injury (IRI) by stimulation on Nei Guan (PC6) and Bai Hui (GV20) points, so that to understand whether or not the protective effects of acupuncture is related to endocytoplasmic reticulum (ER) stressapoptosis passage.
Methods: 50 rats were randomly assigned to five groups (10 in each group): normal control(A), pseudo-operation(B), operation(C), Edaravone(D) and EA(E). The ischemia/reperfusion model of middle cerebral artery occlusion (MCAO) was established by suture embolic method. TUNEL staining method was employed to measure the apoptosis index of nerve cells in rats. Real-time polymerase chain reaction (RT-PCR) was employed to measure the mRNA expression of GRP78 and Caspase-12.
Results: Compared with normal group and pseudo-operation group, the apoptosis indexes and mRNA expression of GRP78 and Caspase-12 in operation group, Edaravone group and EA group were increased, with statistical significance（P＜0.05 or P＜0.01）; compared with operation group, the apoptosis indexes and Caspase-12 mRNA expression in Edaravone group and EA group were decreased（P＜0.05 or P＜0.01）, but GRP78 mRNA expression were increased（P＜0.01）; there were no significant difference between Edaravone group and EA group on the above indexes（P＞0.05).
Conclusion: Acupuncture on Nei Guan and Bai Hui points could effectively suppress the nerve cell apoptosis in cerebral ischemia. The underlying mechanism might be related to upregulation of the ERS-protective GRP78 expression and downregulation of apoptosis-promotion Caspase-12 expression.