CRISPR/Cas9 Reduces Viral Load in a BALB/c Mouse Model of Ocular Herpes Infection

<b>Background/Objectives</b>: <i>Simplexvirus humanalpha1</i> (HSV-1) can cause herpetic keratitis, which is the most common cause of infectious blindness in developed countries. Some patients can develop toxicity or resistance to available treatments and may require keratoplasty. <b>Methods:</b> As an alternative therapy, the CRISPR/Cas9 anti-HSV-1 activity was assessed in an experimental model of BALB/c mice. <b>Results:</b> The results showed that the viral load in the eyes of mice inoculated with HSV-1 at 10⁷ PFU/mL was 4.5 ± 0.2 log₁₀ copies/mL. In contrast, mice inoculated with 10⁹ PFU/mL exhibited a high viral load of 8.1 ± 0.4 log₁₀ copies/mL. The detection of HSV-1 DNA and lesions in the eye was consistent with the viral inoculum of the infection. Next, antiviral activity showed that 200 ng/µL of CRISPR/Cas9 reduced the viral load by 2 logs (<i>p</i> ≤ 0.0001), as well as the lesion scores, compared to the untreated group. <b>Conclusions:</b> Together, the data suggest that CRISPR/Cas9 could be investigated as an alternative therapy for ocular herpes.