Figure 5. Valproic acid (VPA) treatment using alternative dosing schedules started later or every second day reduced the rate of photoreceptor loss in Pde6b^rd1/rd1 mice. White arrows indicate the outer nuclear layer and regions shown at higher magnification (inserts). A: Daily VPA injections (350 mg/kg/day IP) started later from age P14 to P21. Two to three additional layers of photoreceptor cells (nuclei) remained in VPA-treated littermates compared to PBS-treated controls. B: VPA treatment with dosing every second day (350 mg/kg) and the treatment period starting later from age P14 to P21 also reduced the rate of photoreceptor loss (sections are paraffin, hematoxylin and eosin stained).