Fig. 4.

Discontinuation of intranasal insulin therapy in EcoHIV-infected mice with neurocognitive impairment eliminates beneficial effects of insulin on hippocampal dendritic injury and neurocognitive impairment.

Mice were infected and treated with intranasal insulin as described in Fig. 2(a–c) except that the groups (PBS + insulin) and (EcoHIV + insulin) contained 16 mice each. Insulin administration was discontinued in eight mice each in these groups from day 3 of radial arm water maze testing until experiment completion (blue bars in Fig. 2b) and the new groups were labeled (PBS + insulin/disc) and (EcoHIV + insulin/disc). (a) Standard presentation of radial arm water maze results in this experiment showing errors (left panel), latency (middle panel), and visible platform latency (right panel) averaged for the last 3 days of the maze testing. ^∗P < 0.001, ^#P < 0.002. (b) Daily radial arm water maze retention trial results showing errors in finding hidden platform; red arrows indicate when insulin treatment was discontinued; blue-hued columns represent insulin-discontinued mouse groups. ^∗P < 0.001, ^#P < 0.002. (c) Lymphoid and brain HIV burdens. ^∗P < 0.001, ^#P < 0.002. (d) Representative confocal microscope images from the CA1 region of the hippocampus showing detection of neuronal dendritic (MAP2, in green) and nuclear (NeuN, in red) markers; scale bar = 45 μm. (e) Quantification of MAP2 staining in the CA1 and CA3 regions of the hippocampus; ^∗P < 0.01, ^∗∗P < 0.005.