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Methylene Blue Inhibits Acute Hemorrhagic Conjunctivitis Virus Production and Induction of Caspase-3 Mediated Human
Marlyn P Langford1, Alexandra R Sebren1, Maxwell A Burch1
1Department of Ophthalmology, Louisiana State University Health Sciences Center, Shreveport, LA 71130, USA.
Insights
Methylene blue (MB) shows antiviral activity against acute hemorrhagic conjunctivitis (AHC) viruses. MB treatment effectively inhibits AHC virus production and cell damage, supporting its therapeutic potential.
Area of Science:
- Ophthalmology
- Virology
- Pharmacology
Background:
- Acute hemorrhagic conjunctivitis (AHC) is a contagious eye infection caused by enterovirus 70 (E70) and Coxsackievirus A24 variant (CA24v).
- Currently, no specific treatments are approved for AHC.
- Methylene blue (MB), a WHO essential medicine, was investigated for its antiviral properties against AHC viruses.
Purpose of the Study:
- To investigate the antiviral activity of methylene blue (MB) against enterovirus 70 (E70) and Coxsackievirus A24 variant (CA24v).
- To evaluate the efficacy of MB in inhibiting AHC virus replication and cytopathy in human corneal epithelial cells (HCEC).
Main Methods:
- MB accumulation in HCEC was measured colorimetrically.
- MB's inhibition of E70 and CA24v production was assessed using a micro-plaque assay.
- Inhibition of virus-induced cytopathy was determined by measuring caspase-3 activity and DNA fragmentation.
Main Results:
- MB uptake by HCEC was rapid and concentration-dependent.
- MB significantly reduced AHC virus yields (50 to >10,000 fold) in a concentration-dependent manner.
- MB pre-treatment inhibited virus-induced caspase-3 activation and DNA fragmentation, and also reduced cytopathy when applied up to 6 hours post-infection.
Conclusions:
- Methylene blue demonstrates significant potential for treating AHC virus infections.
- MB can inhibit AHC virus production and caspase-mediated cell damage, both before and shortly after infection.
- Ophthalmic solutions containing MB may be a viable therapeutic option for AHC during epidemics.
Background:
Acute hemorrhagic conjunctivitis (AHC) is a highly contagious eye disease caused by enterovirus type 70 (E70) and Coxsackievirus A24 variant (CA24v) with no clinically approved treatment. The antiviral activity of methylene blue (MB; a WHO essential medicine) against AHC viruses was investigated using human corneal epithelial cells (HCEC).
Methods:
Time and concentration-dependent MB accumulation by HCEC was determined colorimetrically and MB inhibition of virus production of 5 E70 and 3 CA24v AHC epidemic isolates in HCEC was determined by micro-plaque assay. AHC virus cytopathy inhibition by MB was detected by reductions in virus-induced caspase-3 activity and polymeric DNA fragments.
Results:
MB uptake by HCEC was rapid and concentration dependent. MB inhibition of E70 and CA24v production was concentration dependent. AHC virus yields were significantly lower (50 to >10,000 fold) in HCEC pre-treated with 0.25-1% MB than in placebo controls (p's ≤ 0.01). MB pre-treatment significantly inhibited virus-induced caspase-3 activation and DNA fragmentation (p's<0.01). Virus-infected cells accumulate oxidized MB and MB application up to 6 h after infection inhibited virus production and virus-induced HCEC cytopathy.
Conclusion:
The results suggest MB treatment prior to and shortly after infection can inhibit AHC virus production and caspase-mediated HCEC cytopathy. The results support the therapeutic potential of ophthalmic solutions containing MB against AHC virus infection during epidemics.
