ABSTRACT
Abstract Introduction The structural changes underlying permanent noise-induced hearing loss (NIHL) include loss of the sensory hair cells, damage to their stereocilia, and supporting tissues within the cochlear lateral wall. Objective The objective of this study is to demonstrate curcumin as a safe and effective therapeutic agent in the prevention and treatment for fibroblasts damage within the cochlear supporting tissues and lateral wall through cell death pathway. Methods We divided 24 Rattus norvegicus into 4 groups, Group 1: control; Group 2: noise (þ); Group 3: noise (þ), 50 mg/day curcumin (þ); Group 4: noise (þ), 100 mg/day curcumin (þ). We provided the noise exposure dose at 100 dB SPL for two hours over two weeks and administered the curcumin orally over two weeks. We examined all samples for the expressions of calcineurin, nuclear factor of activated T-cells cytoplasmic 1 (NFATc1), and apoptotic index of cochlear fibroblasts. Results We found significant differences for the expressions of calcineurin (p< 0.05) in all groups, significant differences for the expressions of NFATc1 (p< 0.05) in all groups, except in Groups 1 and 4, and significant differences for the apoptotic index (p< 0.05) in all groups. Conclusion Curcumin proved to be potentially effective in the prevention and treatment for fibroblasts damage within the cochlear supporting tissues and lateral wall regarding the decreased expression of calcineurin, NFATc1, and apoptotic index of cochlear fibroblasts.
ABSTRACT
One of the five possible mechanisms of leptin resistance in human obesity is the defect in the leptin receptor (Ob-R). Evidence has accumulated that leptin-binding activity in human serum is related to a soluble form of the leptin receptor, and restriction of energy intake resulted a decrease in circulating leptin levels. Aim of this study is to examine the difference of serum soluble leptin receptor level and leptin receptor density in rat adipose tissue of adventitial aorta after four weeks treated with different restricted diets. Soluble leptin receptor level was measured by ELISA and leptin receptor density by using immuno-histochemistry. The soluble leptin receptor in group treated with 40% of normal daily calori diet was found significantly lower than control (p = 0.02). There were no any significant differences among group treated with 40 % of normal daily calori diet, “1 day fast-1day eat”, and ”1day fast-2 days eat” groups, and among 1 day fast-1 day eat”, ”day fast - 2 days eat” and control groups as well. On the other hand, leptin receptor density in adipose tissues was higher in restricted diet group than control. Diet of 40 % normal daily calorie for 4 weeks decreased soluble leptin receptor level, but increased adipocyte leptin receptor density of the adipose tissue of rat adventitial aorta. These changes may be resulted from an up regulation mechanism in relation with homeostatic maintenance.