Hearing Improvement in A/J Mice via the Mouse Nerve Growth Factor

OBJECTIVES: To investigate the otoprotective effects of mouse nerve growth factor (mNGF) in A/J mice. METHODS: The mice at postnatal day 7 (P7) were randomly separated into a mNGF treated group (mNGF group) and a distilled water (for injection) treated group (control group). The mNGF dissolved in distilled water or distilled water alone was given to the mice once every other day from P7 by intramuscular injection in the hips. The otoprotective effects of mNGF in A/J mice were observed in a time course manner. The thresholds of auditory-evoked brainstem response (ABR) were tested from the age of the 3rd to the 8th week. Sections of the inner ears were stained by hematoxylin and eosin, and spiral ganglion neurons (SGNs) were observed at the age of the 3rd, the 6th,and the 8th week. Counts of whole mount outer hair cells (OHCs) in the cochleae were made at the age of 8 weeks. Expression of apoptosis related genes was determined by quantitative real-time polymerase chain reaction and Western blotting. RESULTS: ABR thresholds of the mNGF group were significantly lower than those of the control group at the age of the 6th and the 8th week. Moreover, the mNGF preserved OHC and SGN in the mouse cochleae in this period. Further experiments showed that the expression of caspase genes (including caspase-3) was inhibited in the mouse inner ears in the mNGF group. CONCLUSION: The mNGF improves hearing in A/J mice by preserving SGN and OHC in the cochleae.

Association between variable number of tandem repeat polymorphism of endothelial nitric oxide synthase gene and cerebral infarction / 临床神经病学杂志

Objective To investigate the association between variable number of tandem repeat(VNTR) polymorphism of endothelial nitric oxide synthase(eNOS) gene and cerebral infarction(CI).Methods The genotypes of 152 patients with CI were detected by polymerase chain reaction(PCR) and compared with control group. Multiple regression analysis was performed to assess the independent roles of the polymorphism of eNOS and other risk factors.Results The ab genotype distribution frequency of eNOS gene in CI group(22.36%) was higher than that in control group(12.28%), and a allele frequency of eNOS gene in CI group(12.5%) was also higher than that in control group(7.0%). Both differences between CI group and control group were significant(all P