Related Experiment Video
Updated: Aug 17, 2026
Trans-Tympanic Drug Delivery for the Treatment of Ototoxicity
Published on: March 16, 2018
[Effect of adriamycin on expression of mdr1 gene in guinea pig cochlea lateral wall]
1Department of Otorhinolaryngology, Kunming General Hospital of Chengdu Command, Kunming, 650032, China. yagzhou@yahoo.com.cn
Objective:
To study whether ADM affect the expression of mdr1 gene in guinea pig cochlea lateral wall.
Method:
Sixty white guinea pigs with red eyes were divided into three groups: control group, NS group and ADM group. Guinea pigs were administered an intravenous injection of 30 mg/kg ADM. Four hoars later,ten animals were then immediately sacrificed, and the bony labyrinths were removed. The remaining ten animals were sacrificed after 24 h. The effect of ADM, an ototoxicity drug, on expression of mdrl gene in guinea pigs cochlea lateral walls were observed with RT-PCR. Furthermore, the ADM concentration in endolymph were measured by high performance liquid chromatography.
Result:
For ADM group, the density ratio of mdr1 to beta-action of the 24 h was significantly greater compared to that of the 4 h or controls; In contrast, the ADM concentration of 4 h was significantly higher than that of the 24 h.
Conclusion:
mdr1 gene in normal guinea pig cochlea lateral wall is a stress gene. It can be induced by ADM; it may be not only related to reduce the accumulation of ototoxicity drug in endolymph, but also associated with the protective function of inner ear.
Insights
The multidrug resistance 1 (mdr1) gene in guinea pig cochlea is activated by the ototoxicity drug ADM, suggesting a protective role against drug accumulation in the inner ear.
Area of Science:
- Ototoxicity research
- Gene expression studies
- Inner ear physiology
Context:
- The multidrug resistance 1 (mdr1) gene plays a role in drug transport.
- Aminoglycoside drugs (ADM) are known ototoxic agents.
- Understanding the cochlear response to ototoxic drugs is crucial for inner ear health.
Purpose:
- To investigate the effect of ADM on mdr1 gene expression in the guinea pig cochlea.
- To determine if mdr1 gene expression is altered following ADM administration.
Summary:
- ADM administration significantly increased mdr1 gene expression in the cochlea lateral wall at 24 hours compared to 4 hours or controls.
- Higher ADM concentration was observed in the endolymph at 4 hours than at 24 hours.
- mdr1 gene functions as a stress gene, induced by ADM.
Impact:
- The induction of mdr1 by ADM may help reduce ototoxic drug accumulation in the endolymph.
- This suggests a potential protective mechanism for the inner ear against drug-induced damage.
- Findings contribute to understanding cochlear defense mechanisms against ototoxicity.
