The effects of hyperbaric oxygen therapy upon ototoxic injuries produced by amikacin in guinea pigs

The effect of hyperbaric oxygen therapy combined with hair transplantation surgery for the treatment of alopecia

BACKGROUND

Transplanted hair follicles suffer from various injuries, which are difficult to prevent. Hyperbaric oxygen therapy (HBOT) was reported to be an excellent procedure to promote capillary regeneration and reduce ischemia-reperfusion injury.

AIM

To evaluate the clinical efficacy of HBOT as an adjuvant therapy for hair transplantation surgery.

METHODS

Thirty-four patients with II-IV alopecia were divided into the control group and HBOT group randomly. The control group was treated with routine FUE procedure, while HBOT group combined with HBOT. Patients were treated with 100% oxygen under 2.0 atmospheres absolute pressure for 60 minutes through a facemask during HBOT and take the therapy daily for 7 days continuously after operation. Satisfaction and clinical improvement were evaluated at the fourth week and the sixth month postoperatively.

RESULTS

Itching and folliculitis were significantly decreased in HBOT group (11.8% vs 35.3%). In addition, HBOT resulted in a lower postoperative shedding rate (27.6 ± 2.6% vs 69.1 ± 2.4%); nevertheless, the survival rate at 9 months showed no significant difference between HBOT (96.9 ± 0.5%) and control (93.8 ± 0.6%). The early postoperative satisfaction in control group was much lower than HBOT group (52.9% vs 88.2%), whereas all patients showed satisfaction with the final result.

CONCLUSION

Hyperbaric oxygen therapy is able to minimize the postsurgical follicle shedding and lead to less folliculitis and itching, which provides evidence for HBOT to act as an adjuvant therapy for hair transplantation surgery.

Harderian gland-derived stem cells as a cytotherapy in a guinea pig model of carboplatin-induced hearing loss

BACKGROUND

Stem cells therapy of hearing loss is a challenging field due to lacking self-regenerative capacity of cochlea. Harderian gland of guinea pigs was thought to harbour a unique type of progenitors which could restore the damaged cochlear tissues.

THE AIM

of this study was to isolate Harderian gland derived stem cells (HG-SCs) and investigate their efficacy in restoring the damaged cochlear tissue in carboplatin-induced hearing loss.

METHODOLOGY

Sixty female and 10 male pigmented guinea pigs were used; the male animals were HG-SCs donors, while the females were assigned into 3 groups; control, hearing loss (HL) and HG-SC-treated groups. Auditory reflexes were assessed throughout the study. The animals were euthanized 35 days after HG-SCs transplantation, the cochleae were extracted and processed for assessment by light microscope and scanning electron microscope. Morphometric assessment of stria vascularis thickness, hair cells and spiral ganglia neuronal number and optical density of TLR4 expression were done.

RESULTS

The isolated HG-SCs had the same morphological and phenotypical character as mesenchymal stem cells. HL group revealed destruction of organ of Corti, stria vascularis and spiral ganglion with decreased morphometric parameters. Restoration of both cochlear structure and function was observed in HG-SC-treated group along with a significant increase in IHCs, OHCs numbers, stria vascularis thickness and spiral ganglionic cell count to be close to the values of control group.

CONCLUSION

The isolated HG-SCs were proved to restore structure and function of cochlea in guinea pig model of hearing loss.

Is Hyperbaric Oxygen Therapy Effective in Cisplatin-Induced Ototoxicity in Rats?

Objectives

Cisplatin is an antineoplastic agent, used in the treatment of different types of malignant neoplasms. Side effects such as ototoxicity, nephrotoxicity, and bone marrow toxicity are the main limitations of its clinical use. The aim of the present study was to evaluate the possible effects of hyperbaric oxygen (HBO) therapy as a protective agent in cisplatin-induced ototoxicity in rats.

Methods

A total of 30 adult Wistar rats (60 ears) were divided into five equal groups. Group 1 is a control group; group 2 is HBO therapy group; group 3 received 15 mg/kg cisplatin intraperitoneally; group 4 received 15 mg/kg cisplatin intraperitoneally and HBO treatment on the same day; group 5 received 15 mg/kg cisplatin intraperitoneally and HBO treatment 72 hours later. The effect of ototoxicity was measured with distortion product otoacoustic emission testing performed on the days 1, 3, and 7.

Results

Groups 4 and 5 that received HBO treatment after cisplatin had better signal-to-noise ratio (SNR) values compared with group 3 that received only cisplatin (P<0.05). Compared with group 5, group 4 (same day HBO treatment) had better SNR values (P<0.05).

Conclusion

HBO was found effective for prevention of cisplatin-induced ototoxicity in rats. Our study differs from other studies regarding using a promising treatment, which does not expose subjects to extra stress.

FoxO3a plays a key role in the protective effects of pomegranate peel extract against amikacin-induced ototoxicity

The use of amikacin (AMK) in present treatment strategies results in severe ototoxicity; however, the underlying molecular mechanisms of this toxicity remain unclear. In this study, we investigated the effectiveness of orally administered pomegranate peel extract (PPE), a strong antioxidant, as a protective agent against AMK-induced ototoxicity. To this end, PPE was orally administered to adult BALB/c mice for 5 days, and the mice were then concurrently treated with AMK (500 mg/kg/day for 15 consecutive days). Auditory threshold shifts induced by AMK were significantly attenuated. The results of immunohistochemical staining and western blot analysis revealed that PPE exerted its protective effects by by downregulating the phosphorylation of Forkhead box O3a (FoxO3a), an important transcription factor which is involved in the responses to oxidative stress. The results also showed that PPE treatment inhibited mitogen-activated protein kinase phosphorylation, prevented the activation of pro-apoptotic protein caspase-3, decreased the levels of apoptosis-inducing Bax protein, and increased the levels of the anti-apoptotic mediator, Bcl-2, induced by AMK in the mouse cochlea. Taken together, our experimental findings suggest that phosphorylated FoxO3a mediates AMK-induced apoptosis in BALB/c mice cochlea. PPE effectively attenuated oxidative stress and ototoxicity by regulating FoxO3a, and may thus prove to be beneficial in protecting auditory cells from ototoxic drugs.

Sensorineural deafness following routine transurethral resection of the prostate

A man in his 50s presented to a rural Australian emergency department with complete unilateral hearing loss following transurethral resection of the prostate. His hearing impairment progressed from 'muffled hearing' with tinnitus on emergence from anaesthesia, to total sensorineural deafness by day three. His surgery and anaesthesia were uncomplicated and he had remained normotensive throughout. He had no pre-existing auditory disease. He had received 240 mg of intravenous gentamicin intraoperatively for surgical prophylaxis. Renal function was normal. Brain imaging was negative for structural pathology, stroke and circulatory insufficiency. Ear nose and throat advised 7 days of oral corticosteroids, transtympanic dexamethasone and hyperbaric oxygen therapy. A working diagnosis of gentamicin-induced ototoxicity was applied. Intervention has proven unsuccessful and there is no possibility for rehabilitation. The patient is permanently disabled.

An Evaluation of the Protective Effects of Thymoquinone on Amikacin-Induced Ototoxicity in Rats

Objectives

In this study we investigated the probable protective effects of thymoquinone on amikacin-induced ototoxicity in rats.

Methods

Thirty-two healthy rats were divided into four groups (amikacin, amikacin+thymoquinone, thymoquinone, and no treatment). Thymoquinone was fed to the rats via oral gavage in a dose of 40 mg/kg/day throughout the study period of 14 days. Amikacin was given by the intramuscular route in a dose of 600 mg/kg/day. Audiological assessment was conducted by the distortion product otoacoustic emission (DPOAE) and auditory brainstem response (ABR) tests, administered to all rats at the beginning of the study, and also on days 7 and 15. Biochemical parameters were calculated at the termination of the study to evaluate the oxidative status.

Results

There were significant decreases in DPOAE values and significant increases in ABR thresholds of the amikacin group on days 7 and 15, as compared to the amikacin+thymoquinone group. While ABR thresholds of the amikacin group increased significantly on days 7 and 15 as compared to their initial values, there were no significant differences between the initial and the 7th and 15th day values of ABR thresholds in the amikacin+thymoquinone group. Total oxidant status and oxidative stress index values of the amikacin+thymoquinone group were significantly lower than those of the amikacin group. Total antioxidant status values of the amikacin+thymoquinone group were significantly higher than those of the amikacin group.

Conclusion

Our study has demonstrated that the ototoxic effect brought forth by amikacin could be overcome with the concurrent use of thymoquinone.

Betahistine exacerbates amikacin ototoxicity

OBJECTIVE

Betahistine augments cochlear blood flow and is currently used as an efficient therapeutic agent. Amikacin is used in a wide range of areas, but its ototoxic effect continues to be problematic. This study investigates the effect of betahistine on amikacin-induced ototoxicity.

METHODS

Thirty-two healthy rats were randomized to 4 groups of 8 rats in each group (amikacin, amikacin+betahistine, betahistine, and no treatment). Amikacin was administered intramuscularly to groups 1 and 2 for 14 days. Betahistine was delivered by oral gavage to groups 2 and 3 for 21 days. Distortion-product otoacoustic emissions (DPOAE) and auditory brainstem response (ABR) tests were conducted on all rats.

RESULTS

There were significant decreases in the DPOAE levels and significant increases in the ABR thresholds of the amikacin and amikacin+betahistine groups on the 7th, 14th, and 21st days, as compared to their basal values. The DPOAE levels of the amikacin+betahistine group significantly decreased on days 7, 14, and 21, and the ABR thresholds significantly increased on the same days, as compared to the amikacin group.

CONCLUSION

Our study implies that amikacin's ototoxic effects are augmented by the concurrent use of betahistine. Experimental and clinical research, supported by histopathological studies, is needed to affirm our findings.

Protective effect of trimetazidine on amikacin-induced ototoxicity in rats

OBJECTIVE

Aminoglycoside antibiotics are known to have ototoxic effects and may induce sensorineural hearing loss. This study investigated the protective effect of trimetazidine, which has antioxidant and cytoprotective properties, against amikacin ototoxicity.

METHODS

Thirty-two male rats were divided into four groups - amikacin, amikacin + trimetazidine, trimetazidine, and control groups. Trimetazidine, 10 mg/kg per day, was given for 14 days by oral gavage. Amikacin, 600 mg/kg per day, was also given for 14 days, by the intramuscular route. Distortion product otoacoustic emission (DPOAE) and auditory brainstem response (ABR) tests were applied to the rats for hearing assessment. At the termination of the study, the biochemical parameters were calculated to evaluate the oxidative status.

RESULTS

The DPOAE values of the amikacin group were significantly lower on the 7th and 14th days than those of the trimetazidine + amikacin group and there was an increase in the ABR thresholds. The ABR thresholds for the amikacin group on the 7th and 14th days were significantly higher than the levels on the first day of the study, while there was no significant increase in those values in the trimetazidine + amikacin group. The total oxidant status (TOS) and oxidant status index (OSI) values of the amikacin group were significantly higher than those of the trimetazidine + amikacin group. The total antioxidant status (TAS) values of the amikacin group were lower than those of the trimetazidine + amikacin group.

CONCLUSIONS

The audiologic tests and biochemical parameters investigated in this study both point to the protective effect of trimetazidine against amikacin-induced ototoxicity.