ABSTRACT
RhoA, a small GTPase, is involved in a wide array of cellular functions in the central nervous system, such as cell motility, cytoskeleton rearrangement, transcriptional regulation, phagocytosis and cell growth. It is not known how spinal cord injury (SCI) affects the expression of RhoA in different nerve cells. In the present study, we investigated the changes of RhoA expression in remote areas of the injury at the 3rd, 7th and 30th day after SCI, which was established by T10 contusion method. Moreover, we examine its expression profile in neurons, astrocytes and microglia. RhoA was found to be weakly expressed in these nerve cells in normal spinal cord. Western blotting showed that, after SCI, the total RhoA expression was up-regulated, and the RhoA expression was increased and peaked at the 7th day. Double immunostaining revealed specific and temporal expression patterns of RhoA in different nerve cells. The expression of RhoA in neurons started to increase at day 3, peaked at day 7 and then decreased slightly at day 30. Expression of RhoA in astrocytes increased moderately after SCI and peaked at day 7. There was no obvious change in RhoA expression in microglia after SCI in remote areas. This study demonstrated that, after SCI, RhoA expression exhibited different patterns with different nerve cells of spinal cord. RhoA expression patterns also changed with time after SCI, and among different nerve cells in the injured spinal cord. These findings can help us better understand the roles of RhoA in SCI.
ABSTRACT
RhoA, a small GTPase, is involved in a wide array of cellular functions in the central nervous system, such as cell motility, cytoskeleton rearrangement, transcriptional regulation, phagocytosis and cell growth. It is not known how spinal cord injury (SCI) affects the expression of RhoA in different nerve cells. In the present study, we investigated the changes of RhoA expression in remote areas of the injury at the 3rd, 7th and 30th day after SCI, which was established by T10 contusion method. Moreover, we examine its expression profile in neurons, astrocytes and microglia. RhoA was found to be weakly expressed in these nerve cells in normal spinal cord. Western blotting showed that, after SCI, the total RhoA expression was up-regulated, and the RhoA expression was increased and peaked at the 7th day. Double immunostaining revealed specific and temporal expression patterns of RhoA in different nerve cells. The expression of RhoA in neurons started to increase at day 3, peaked at day 7 and then decreased slightly at day 30. Expression of RhoA in astrocytes increased moderately after SCI and peaked at day 7. There was no obvious change in RhoA expression in microglia after SCI in remote areas. This study demonstrated that, after SCI, RhoA expression exhibited different patterns with different nerve cells of spinal cord. RhoA expression patterns also changed with time after SCI, and among different nerve cells in the injured spinal cord. These findings can help us better understand the roles of RhoA in SCI.
Subject(s)
Animals , Male , Astrocytes , Metabolism , Blotting, Western , Immunohistochemistry , Microglia , Metabolism , Microscopy, Confocal , Neurons , Metabolism , Rats, Sprague-Dawley , Spinal Cord Injuries , Metabolism , Time Factors , rhoA GTP-Binding Protein , MetabolismABSTRACT
<p><b>OBJECTIVE</b>To compare the long-term efficiency between preoperative radiotherapy or radiochemotherapy followed by lower-anterior resection and abdominoperineal resection (APR) for lower and locally advanced rectal cancer.</p><p><b>METHODS</b>From January 1983 to December 2000, 157 consecutive patients suffering from lower rectal cancer were enrolled in the study, which included 69 cases of clinical stage II and 88 cases of stage III respectively. All patients were divided in to three groups. Patients in group A (n=52) received preoperative radiotherapy with a total dose of 35-45 Gy within 4-5 weeks plus preoperative chemotherapy with 5-fluorouracil (5- FU) followed by lower-anterior resection; patients in group B (n=51) received radiotherapy followed by lower-anterior resection; patients in group C (n=54) received APR only. Clinical data of all patients were reviewed retrospectively.</p><p><b>RESULTS</b>The follow-up rate was 91.7%. The 5- year survival rate was higher in group A (71.1%) than those in group B (47.1%) and group C (42.6%)(P< 0.05). The tumor- free survival rate was higher in group A (61.5%) than those in group B (37.3%) and group C (35.2%)(P< 0.05). The local recurrence rate was 13.5%, 15.7% and 11.1% in group A, B and C respectively, there was no significant difference in recurrence rate among three groups (P> 0.05). The distant metastasis rate was lower in group A (23.1%) than those in group B (49.0%) and group C (46.3%)(P< 0.05), but there was no significant difference in distant metastasis rate between group B and group C.</p><p><b>CONCLUSIONS</b>The combined preoperative radiochemotherapy followed by lower-anterior resection can improve the 5-year survival rate and tumor-free survival rate, and decrease distal metastasis rate.</p>