Fig 1. Experimental design.

Postnatal day 7 rats were subjected to unilateral HI brain injury and received intraperitoneal injections of either melatonin 10 mg/kg dissolved in DMSO 5% and PBS or vehicle (DMSO 5% and/or PBS) at 0, 6 and 25 hours after hypoxia. Littermate controls were sham-operated. Within 1 day after HI, in-vivo MR imaging including ADC maps and T₂-w images was performed. T₂-w images and DTI were repeated at 7, 20 and 43 days after HI followed by histological and immunohistochemical analysis. Functional testing, including the cylinder rearing test and the novel object recognition test, was performed at 2 and 5–6 weeks after HI. ADC, apparent diffusion coefficient; DMSO, dimethyl sulfoxide; DTI, diffusion tensor imaging; HI, hypoxia-ischemia; MRI, magnetic resonance imaging; PBS, phosphate-buffered saline.