Downregulation of KCNMA1 in mice accelerates auditory hair cells senescence via ferroptosis.

KCNMA1 encodes the K+ potassium channel α-subunit that plays a significant role in the auditory system. Our previous studies indicated that KCNMA1 is associated with age-related hearing loss(AHL). However, the detailed mechanism of KCNMA1 involvement in auditory age-related degradation has not been fully clarified. Therefore, we explored the expression of KCNMA1 in the peripheral auditory of 2-month-old and 12-month-old mice by Western blotting and immunofluorescence. The results of animal experiments showed that KCNMA1 expression was decreased in 12-month-old mice compared with 2-month-old mice, whereas the ferroptosis level was increased. To verify the role of KCNMA1 in AHL, we downregulated KCNMA1 in HEI-OC1 cells by transfecting shRNA. After downregulation, the ferroptosis level was increased and the aging process was accelerated. Furthermore, the aging process was affected by the expression of ferroptosis. In conclusion, these results revealed that KCNMA1 is associated with the aging process in auditory hair cells by regulating ferroptosis, which deepens our understanding of age-related hearing loss.

[Study on correlation between serum vitamin D level and the curative effect after repair of rotator cuff tears].

OBJECTIVE: To investigate the correlation between serum vitamin D level and clinical outcomes after repair of rotator cuff tears. METHODS: A total 122 patients who met the inclusion criteria and were followed up for 12 months from March 2018 to March 2020 were analyzed retrospectively, including 50 males and 72 females with an average age of(62.10±8.39) years old (ranged, 34 to 82 years old). All patients were divided into deficiency group(vitamin D<20 µg/L) and control group(vitamin D≥20 µg/L), including 62 cases in the deficiency group, with vitamin D (14.80±3.18) µg/L;60 cases in the control group, with vitamin D(25.17±5.64) µg/L. The two groups were compared in terms of age, gender, body mass index(BMI), tear size, degree of retraction, degree of fatty infiltration, injury factors, postoperative pain VAS score, postoperative shoulder joint function score, and re-tear rate. The age of all patients was divided into two categories:<60 years old and ≥60 years old;BMI was divided into <24 kg/m2 and ≥ 24 kg/m2;tear size was divided into ≤3 cm and >3 cm;retraction degree was divided into ≤2 cm and >2 cm;fat infiltration was divided into ≤2 grade and >2 grade;and the course of the disease was ≤3 months and >3 months. The correlation between Sugaya re-tear type and the variables listed above were analyzed and calculated. RESULTS: There were no major complications such as joint infection, anchor withdrawal and revision surgery in any of the 122 patients who were followed up on. There were no statistical differences in age, gender, injury factor, BMI, tear size, degree of retraction, degree of fatty infiltration, and duration of disease between the two groups (P>0.05). The Constant-Murley scores, UCLA scores, and ASES scores of the two groups all improved considerably after surgery(P<0.05);however, there was no statistical differences in the postoperative shoulder function scores between the two groups (P>0.05). There was significant difference in VAS between the two groups 1 month and 3 months after operation, with vitamin D deficiency group scoring higher, and there was no significant differences 6 and 12 months after operation. Tear size(>3 cm), degree of retraction(>2 cm), degree of fatty infiltration(>2 degree) were all shown to be the independent risk factors for retear after surgery by Logistic regression analysis(P<0.05). The comparison between the two groups of patients using a 2×5 row list showed that the Sugaya classification of rotator cuff re-tear(grade Ⅰto Ⅴ) between the vitamin D deficiency group and the control group was statistically different(t=14.228, P=0.007). It was discovered that the Sugaya classification after surgery was statistically different between the two groups. CONCLUSION: Vitamin D deficiency is not correlated with clinical function scores and re-tear rate, however it is associated with the early postoperative pain (1 and 3 months) and the quality of rotator cuff healing (Sugaya classification) after surgery.