GFAP and Fos immunoreactivity in lumbo-sacral spinal cord and medulla oblongata after chronic colonic inflammation in rats

AIM： To investigate the response of astrocytes and neurons in rat lumbo±sacral spinal cord and medulla oblongata induced by chronic colonic inflammation, and the relationship between them. METHODS： Thirty-three male Sprague-Dawley rats were randomly divided into two groups： experimental group （n = 17）, colonic inflammation was induced by intra-luminal administration of trinitrobenzenesulfonic acid （TNBS）; control group （n = 16）, saline was administered intra-luminally. After 3, 7, 14, and 28 d of administration, the lumbo-sacral spinal cord and medulla oblongata were removed and processed for anti-glial fibrillary acidic protein （GFAP）, Fos and GFAP/Fos immunohistochemistry. RESULTS： Activated astrocytes positive for GFAP were mainly distributed in the superficial laminae （laminae Ⅰ-Ⅱ） of dorsal horn, intermediolateral nucleus （laminae Ⅴ）, posterior commissural nucleus （laminae Ⅹ） and anterolateral nucleus （laminae Ⅸ）. Fos-IR （Fos-immunoreactive） neurons were mainly distributed in the deeper laminae of the spinal cord （laminae Ⅲ-Ⅳ, Ⅴ-Ⅵ）. In the medulla oblongata, both GFAP-IR astrocytes and Fos-IR neurons were mainly distributed in the medullary visceral zone （MVZ）. The density of GFAP in the spinal cord of experimental rats was significantly higher after 3, 7, and 14 d of TNBS administration compared with the controls （50.44±16.8, 29.24±6.5, 24.14±5.6, P〈0.05）. The density of GFAP in MVZ was significantly higher after 3 d of TNBS administration （34.34±2.5, P〈0.05）. After 28 d of TNBS administration, the density of GFAP in the spinal cord and MVZ decreased and became comparable to that of the controls （18.04±4.9, 14.64±6.4, P〉0.05）. CONCLUSION： Astrocytes in spinal cord and medulla oblongata can be activated by colonic inflammation. The activated astrocytes are closely related to Fos-IR neurons. With the recovery of colonic inflammation, the activity ofastrocytes in the spinal cord and medulla oblongata is reduced.

Research on Acupuncture Regulation of Visual Cortex c-Fos Protein Expression in Monocular Deprivation Cats

Objective： To explore the mechanism underlying acupuncture regulation of the visual cortex plasticity. Methods： Eighteen kittens of four weeks were randomly divided into 3 groups, a normal group, a model group and an acupuncture group, with six in each group. There was no treatment to those in the normal group. Unilateral eyelid suture method was used to establish the deprivation amblyopia cat model in the model group and the acupuncture group. After that, kittens in the model group didn＇t receive any treatment, but those in the acupuncture group were treated with acupuncture therapy of 12 weeks. Pattern Visual Evoked Potential （P-VEP） and c-Fos protein expression of visual cortex of kittens in each group were tested before and after acupuncture treatment. Results： P-VEP waveform changed significantly in kittens of the model group, the time value of P100was significantly delayed （P〈0.01） and N4s-P100 amplitude was significantly lower （P〈0.01） compared with the normal group. After treatment, the time value of P100in kittens of the acupuncture group was significantly shorter （P〈0.01） and N4s-P100 amplitude was significantly higher （P〈0.01） when compared with the model group. Expression of c-Fos positive neurons can be seen in the visual cortex layers II-IV of kittens in the acupuncture group, and the density and percentage of c-Fos immunoreactive neurons of cortex layers II-IV in kittens of the model group were significantly lower than those in the acupuncture group. Conclusion： Acupuncture has obvious improvement for abnormal changes of P-VEP waveform of monocular visual deprivation kittens; it can also increase the c-Fos protein expression in visual cortex after form- deprived.

Decline in the expression of IL-2 after trauma and changes in the nuclear transcription factors NFAT and AP-1

OBJECTIVE: To investigate whether the decrease in expression of interleukin-2 (IL-2) after trauma is associated with changes in DNA binding activity of nuclear factor of activated T cells (NFAT) and activator protein-1 (AP-1). METHODS: Mice with closed impact injury with fracture in both hind limbs were adopted as the trauma model. Spleen lymphocytes were isolated from traumatized mice and stimulated with Con-A. Culture supernatants were assayed for IL-2 activity, and total RNA was extracted from spleen lymphocytes and assayed for IL-2 mRNA. DNA binding activity of NFAT and AP-1 were measured by electrophoretic mobility shift assay (EMSA). The expression of c-Fos, c-Jun and JunB proteins was determined by the Western blot analysis. RESULTS: DNA binding activity of NFAT and AP-1 gradually decreased to a minimum of 41% and 49%, respectively, of the control on the 4th day after injury, which was closely followed by the decline in IL-2 activity and IL-2 mRNA. A decrease in the expression of c-Fos on the 1st and 4th day after trauma had no significant effect on c-Jun expression; the increase in expression of JunB was only on the 1st day after injury. CONCLUSION: Decreased IL-2 expression is, at least in part, due to a decline in the activation of NFAT and AP-1 in traumatized mice. The decline in DNA binding activity of NFAT and AP-1 is partly due to a trauma-induced block in the expression of c-Fos.