OBJECTIVETo investigate the changes in the morphology and cytoskeleton (CSL) content of the CSL in the colonic smooth muscle cells (SMCs) of rats in early postscald stage, so as to elucidate the mechanism of dysfunction of gastrointestinal motility.

METHODSSeventy Wistar rats were randomly divided into normal control (n = 10, without scald) , and scald ( n = 60, with 10 cm x 7 cm wound inflicted on the back) groups. The colonic smooth muscle tissue of 10 normal rats and scalded rats were harvested at 1, 3, 6, 12, 24 and 48 postscald hours( PSH) and divided into two parts: one for histologic examination, and the other for the detection of CSL changes in the colonic smooth muscle tissue by flowcytometry method.

RESULTSThe electron microscope examination showed that the arrangement of cytoskeleton of SMC of the scalded rats during 1 to 3 PSH was disordered, and sparse, and the condensed area was uneven, with fragmentation. But the morphology and distribution of CSL gradually restored to normal state during 6 to 12 PSH, and it approached that of normal group at 48 PSH. The CSL content in the colonic smooth muscle tissue of scalded rats was obviously increased at 1 PSH (610+/-23) , decreased thereafter, evidently lower than that in control group at 3 PSH (92+/-17) , and then it started to increase at 12 PSH, exceeding the normal value at 24 PSH, and continued to rise until 48 PSH. There was significant difference in CSL content in the colonic smooth muscle tissue of the rats between scald and control group ( P < 0.05 or 0. 01).

CONCLUSIONChanges in the morphology and CSL content in the colonic smooth muscle tissue can be observed at early stage after a scald, which imply the kinetic balance between damage and repair in the body. In addition, changes in CSL content in the colonic smooth muscle tissue may be important factors in producing colonic dysfunction, damage of intestinal wall structure, and dynamic abnormalities of the colonic smooth muscle.