Figure 1: A deficiency in STAT3 activation in GFAP⁺ NSCs and astrocytes in Trpv1^−/− mouse brains upon the peripheral LPS stimulation.

C57BL/6J mice received an intraperitoneal administration of 50 μg/kg LPS and were sacrificed for STAT3 immunohistochemistry. (a,b) The nuclear translocation of STAT3 was often observed in GFAP⁺ NSCs in sensory CVOs (OVLT, SFO, and AP) and thermoregulatory hypothalamic subregions (MnPO and POA) in Trpv1^+/+ mice 2 hr after the peripheral LPS stimulation (top and middle panels in a), while it was rarely observed in Trpv1^−/− mice (b). A three-dimensional image analysis demonstrated the presence of STAT3⁺ nuclei in GFAP⁺ NSCs and astrocytes (bottom panels in a). Arrowheads indicate STAT3⁺ nuclei in GFAP⁺ cells. Scale bars = 50 (top panels of a,b) and 10 (bottom panels of a) μm. (c) The quantitative analysis showed that the number of STAT3⁺ GFAP⁺ cells in Trpv1^+/+ mice was significantly increased in sensory CVOs and hypothalamic thermoregulatory brain subregions after the intraperitoneal administration of 50 μg/kg LPS, but was not in Trpv1^−/− mice. Sol, solitary nucleus; 3V, 3^rd ventricle. Data (n = 4) were expressed as the mean (±s.e.m.). ^*P < 0.05, ^***P < 0.001 vs the vehicle in Trpv1^+/+ mice and ^#P < 0.05, ^###P < 0.001 between Trpv1^+/+ and Trpv1^−/− mice by ANOVA with Turkey’s post hoc tests.