| Objective: To explore the relationships between electroretinogram responses and the expression of alpha B-crystallin, ALDH2 and ATP5A1 in rat retina and vitreous humor after methanol intoxication.Methods: Sprague-Dawley rats were divided into groups for a control(group A) and 3-(group B) and 7-day(group C) intoxication treatment. Retinal function of each group was assessed by recording electroretinogram responses. Methanol and formic acid concentrations in blood and formic acid concentrations in tissues were detected by chromatography. Expression of alpha B-crystallin, ALDH2 and ATP5A1 in retina and vitreous humor were measured by western blot assay.Results: For Rod-response of ERG, the a and b amplitudes of group B decreased approximately to 53% and 37% and b amplitude of group C decreased approximately to 48% compared with the control group(p<0.05). For Max-response, the a and b amplitudes of group B decreased approximately to 53% and 40% and b amplitude of group C decreased approximately to 44% compared with the control group(p<0.05).The latent periods of a wavelet in group B delayed approximately to 26% in Max-response, and latent period of a wavelet in group C delayed approximately to 28% compared with the control group(p<0.05). The summed amplitudes of oscillation potentials in group B and C decreased to approximately 53% and 57% compared with the control(p<0.05) and the elapsed time delayed to approximately 15% and 60%(p<0.05). The amplitudes of OS1, OS3, OS4, OS5 of group B and OS3, OS4, OS5 of group C decreased compared with the control group(p<0.05). Comparison of OS1 between B and C groups was statistically significant(p<0.05). The IPI1 of group B and IPI1-4 of group C were broader compared with the control group(p<0.05) and the IPI1-4 in group B were broader than in group C(p<0.05). For Con-response, the a and b amplitudes of group B decreased approximately to 53% and 40% and b amplitude of group C decreased approximately to 69% compared with the control group(p<0.05). Comparison of b amplitude between B and C groups was statistically significant(p<0.05). The latent periods for a and b wavelets of group C delayed approximately to 29% and 9% compared with the control group(p<0.05). The methanol concentration in blood was 1.0 mg/mL in group B, whereas it was below the headspace gas chromatography detection threshold in group C. The formic acid concentrations in blood were nearly identical in both B and C groups, 0.61mg/mL and 0.60mg/mL respectively. Compared with group B, there was an increase for formic acid concentrations in brain and stomach in group C and a decrease in liver and kidney. Alpha B-crystallin, ALDH2 and ATP5A1 were highly expressed in the mixture of rat retina and vitreous humor after methanol poisoning, and this high expression was more remarkable in group C than in group B. No apparent alpha B-crystallin was detected in retina and the expression of ALDH2 and ATP5A1 were apparently unaltered in group B, while alpha B-crystallin, ALDH2 and ATP5A1 in group C were down-regulated in retina compared with the control. In vitreous humor, alpha B-crystallin was apparently unaltered in group B and up-regulated in group C. ALDH2 and ATP5A1 in vitreous humor were up-regulated in both B and C groups, and this high expression of ALDH2 and ATP5A1 was more apparent in group C than in group B.Conclusions: The present results indicated that eletroretinogram responses were impaired after methanol poisoning and the effect more serious in the 7-day than the 3-day group, which might had been due to formic acid accumulation after methanol ingestion. Compared with retina, altered expression of alpha B-crystallin, ALDH2 and ATP5A1 in vitreous humor were more appropriate to be biological signals for retinal toxicity and function impairment after methanol intoxication. There appeared to be potential relationships between retinal function, formic acid accumulation, and expression of these three proteins, which need to be deeply explored. |
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