J Clin Med Res

Journal of Clinical Medicine Research, ISSN 1918-3003 print, 1918-3011 online, Open Access

Article copyright, the authors; Journal compilation copyright, J Clin Med Res and Elmer Press Inc

Journal website http://www.jocmr.org

Original Article

Volume 9, Number 11, November 2017, pages 900-906

Study of Methylene Blue Ototoxicity in the Guinea Pig

Figure 2. Mean threshold of differences in each group. (a) Mean threshold of differences in the control group (normal saline vs. gentamicin). (b) Mean threshold of differences in the experimental group (normal saline vs. methylene blue).

Figure 3. Normal saline group: DAPI stain (a) and FITC stain (b). Gentamicin group: DAPI stain (c) and FITC stain (d). Methylene blue group: DAPI stain (e) and FITC stain (g) (× 20). DAPI: 4',6-diamidino-2-phenylindole; FITC: fluorescein isothiocyanate.

**Table 1.** Auditory Brainstem Responses Thresholds in Decibel for the Control Group (Normal Saline vs. Gentamicin) Before and After the Completion of the Intratympanic Injections
Frequencies	Normal saline	Gentamicin
Thresholds are shown in decibels ± standard deviation.
2,000 Hz	29.00 ± 6.58	37.00 ± 8.88	8.00 ± 8.23	30.50 ± 6.85	105.00 ± 28.28	74.50 ± 28.62
4,000 Hz	31.00 ± 11.25	33.50 ± 9.73	2.50 ± 4.25	27.50 ± 9.79	98.00 ± 25.95	70.50 ± 28.43
6,000 Hz	24.50 ± 11.17	25.50 ± 7.98	1.00 ± 5.68	19.00 ± 10.49	86.00 ± 23.19	67.00 ± 26.06
8,000 Hz	9.50 ± 10.39	7.50 ± 8.90	-2.00 ± 5.37	4.00 ± 5.68	66.50 ± 25.83	62.50 ± 23.07
Mean dB	23.50 ± 8.68	25.88 ± 7.34	2.38 ± 4.62	20.25 ± 6.53	88.88 ± 25.19	68.63 ± 26.20

Table 1. Auditory Brainstem Responses Thresholds in Decibel for the Control Group (Normal Saline vs. Gentamicin) Before and After the Completion of the Intratympanic Injections

Frequencies

Normal saline

Gentamicin

Before

After

Hearing loss

Before

After

Hearing loss

Thresholds are shown in decibels ± standard deviation.

2,000 Hz

29.00 ± 6.58

37.00 ± 8.88

8.00 ± 8.23

30.50 ± 6.85

105.00 ± 28.28

74.50 ± 28.62

4,000 Hz

31.00 ± 11.25

33.50 ± 9.73

2.50 ± 4.25

27.50 ± 9.79

98.00 ± 25.95

70.50 ± 28.43

6,000 Hz

24.50 ± 11.17

25.50 ± 7.98

1.00 ± 5.68

19.00 ± 10.49

86.00 ± 23.19

67.00 ± 26.06

8,000 Hz

9.50 ± 10.39

7.50 ± 8.90

-2.00 ± 5.37

4.00 ± 5.68

66.50 ± 25.83

62.50 ± 23.07

Mean dB

23.50 ± 8.68

25.88 ± 7.34

2.38 ± 4.62

20.25 ± 6.53

88.88 ± 25.19

68.63 ± 26.20

**Table 2.** Auditory Brainstem Response Thresholds in Decibel for the Methylene Blue Group Before and After the Intratympanic Injections
Frequencies	Normal saline	Methylene blue
Thresholds are shown in decibels ± standard deviation.
2,000 Hz	32.50 ± 8.58	33.00 ± 11.60	0.50 ± 6.85	38.00 ± 6.32	41.00 ± 13.08	3.00 ± 14.18
4,000 Hz	24.00 ± 7.75	26.00 ± 13.29	2.00 ± 12.52	27.50 ± 6.35	30.50 ± 11.41	3.00 ± 11.83
6,000 Hz	14.50 ± 4.97	16.50 ± 13.34	2.00 ± 12.74	17.50 ± 4.86	20.00 ± 11.79	2.50 ± 12.08
8,000 Hz	-0.50 ± 5.50	0.00 ± 10.54	0.50 ± 10.66	2.50 ± 6.35	5.00 ± 11.55	2.50 ± 11.37
Mean	17.63 ± 6.25	18.88 ± 11.85	1.25 ± 10.47	21.38 ± 5.25	24.13 ± 11.40	2.75 ± 11.71

Table 2. Auditory Brainstem Response Thresholds in Decibel for the Methylene Blue Group Before and After the Intratympanic Injections

Frequencies

Normal saline

Methylene blue

Before

After

Hearing loss

Before

After

Hearing loss

Thresholds are shown in decibels ± standard deviation.

2,000 Hz

32.50 ± 8.58

33.00 ± 11.60

0.50 ± 6.85

38.00 ± 6.32

41.00 ± 13.08

3.00 ± 14.18

4,000 Hz

24.00 ± 7.75

26.00 ± 13.29

2.00 ± 12.52

27.50 ± 6.35

30.50 ± 11.41

3.00 ± 11.83

6,000 Hz

14.50 ± 4.97

16.50 ± 13.34

2.00 ± 12.74

17.50 ± 4.86

20.00 ± 11.79

2.50 ± 12.08

8,000 Hz

-0.50 ± 5.50

0.00 ± 10.54

0.50 ± 10.66

2.50 ± 6.35

5.00 ± 11.55

2.50 ± 11.37

Mean

17.63 ± 6.25

18.88 ± 11.85

1.25 ± 10.47

21.38 ± 5.25

24.13 ± 11.40

2.75 ± 11.71