Amelioration of Auditory Response by DA9801 in Diabetic Mouse

Diabetes-induced auditory complications: are they preventable? a comprehensive review of interventions

Diabetes mellitus is a chronic metabolic disorder characterized by elevated blood glucose levels, which, over time, lead to major chronic complications in various organs of the body. A growing body of research suggests that diabetes could also result in degenerative changes in the auditory system. To date, several attempts have been made to prevent and reduce diabetes-induced auditory complications. Such attempts have generally focused on disease modifying as well as other pharmacological treatments involving several herbal and non-herbal agents such as vitamins C and E, rutin, resveratrol, coffee, trigonelline, Dioscorea nipponica, red ginseng, Pterostilbene Bofutsushosan, Daisaikoto, tolrestat, ACE inhibitors (enalapril), Ca antagonists (nimodipine), Lipo-prostaglandin E1, methylprednisolone, dexamethasone, and chlorogenic acid and also other strategies like acupuncture. However, there is no consensus about which are the most effective strategies for preventing and reducing auditory complications in diabetic patients with few side effects and maximum efficacy. This paper provides a comprehensive review of interventions for preventing and treating diabetes-induced auditory complications to help therapists.

Involvement of Organic Anion Transporters in the Pharmacokinetics and Drug Interaction of Rosmarinic Acid

We investigated the involvement of drug transporters in the pharmacokinetics of rosmarinic acid in rats as well as the transporter-mediated drug interaction potential of rosmarinic acid in HEK293 cells overexpressing clinically important solute carrier transporters and also in rats. Intravenously injected rosmarinic acid showed bi-exponential decay and unchanged rosmarinic acid was mainly eliminated by urinary excretion, suggesting the involvement of transporters in its renal excretion. Rosmarinic acid showed organic anion transporter (OAT)1-mediated active transport with a K_m of 26.5 μM and a V_max of 69.0 pmol/min in HEK293 cells overexpressing OAT1, and the plasma concentrations of rosmarinic acid were increased by the co-injection of probenecid because of decreased renal excretion due to OAT1 inhibition. Rosmarinic acid inhibited the transport activities of OAT1, OAT3, organic anion transporting polypeptide (OATP)1B1, and OATP1B3 with IC₅₀ values of 60.6 μM, 1.52 μM, 74.8 μM, and 91.3 μM, respectively, and the inhibitory effect of rosmarinic acid on OAT3 transport activity caused an in vivo pharmacokinetic interaction with furosemide by inhibiting its renal excretion and by increasing its plasma concentration. In conclusion, OAT1 and OAT3 are the major transporters that may regulate the pharmacokinetic properties of rosmarinic acid and may cause herb-drug interactions with rosmarinic acid, although their clinical relevance awaits further evaluation.

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.