European Journal of Biomedical and Pharmaceutical Sciences

ALTERATIONS IN COCHLEAR ANTIOXIDANT LEVELS & HAIR CELL PROTEINS OF SPRAGUE DAWLEY (SD) RATS EXPOSED TO CHRONIC NOISE EXPOSURE

Nivetha Ravishankar*, Dr. Dheepthi Jayamurali, Dr. Pazhanisankar Muthusamy, Jeyakumari Paul, Dr. Ravindran Rajan*

ABSTRACT

The sound that is beyond the normal range is considered noise. Noise is supposed to be an alarming environmental pollutant. It also affects various bodily functions. Exposure to noise over a long period leads to permanent hearing impairment and cochlear dysfunction known as Noise-Induced Hearing Loss (NIHL). The current aim of the study is to observe the cochlear proteins, biochemical changes in the inner ear after chronic noise exposure and the role of a synthetic steroid (Prednisolone) when given at a low dose as treatment. Sprague Dawley (SD) rats weighing about 250-300g were grouped into 4 groups: Group I- Control, Group II- Chronic Noise Exposure (100dBA 4 hours/day for 30 days), Group III -Treatment (Prednisolone,1mg/kg b.w. administered orally, dissolved in 0.9% Saline given for 7 days after the noise exposure), Group IV- Drug only. After 30 days of noise exposure, anxiety behaviour, such as the Open Field Test (OFT) and Elevated Plus Maze (EPM), has been observed, and the results are interpreted using the software ANYMAZE. The animals are then euthanised, then the inner ear is harvested for antioxidant assays, Plasma Corticosterone estimation and protein estimations using the ELISA kits. Our study demonstrates the behavioural changes and protein estimations which was altered in the noise-exposed groups that haven‟t shown effectiveness against the treatment with a low dose of prednisolone, while the biochemical assay observed in the inner ear shows reduced oxidative stress with the treatment of prednisolone. From the results obtained, it has been concluded that a low dose of prednisolone can be used to lower the oxidative stress alone, but furthermore, more studies should be carried out to check the negative effect on behaviour and protein estimations.

Keywords: Hearing loss, Cochlear Hair cells, Prednisolone, inner ear antioxidants. Chronic noise exposure.