OBJECTIVE: To probe into the therapeutic effects of dexmedetomidine on colon cancer model rats and its effects on Ras homolog gene family member A（RhoA）/Rho-associated coiled-coil containing protein kinase 1（ROCK1） signal pathway. METHODS: The rat model of colon cancer was induced by 1

2-dimethylhydrazine

the model rats were randomly divided into the model group and low-dose（25 μg/kg）

medium-dose（50 μg/kg）

high-dose（100 μg/kg） dexmedetomidine group

with 6 rats in each group. Another 6 rats without model were taken as the normal group. Each group was treated with corresponding drugs for 4 weeks

the general condition of rats was observed. The serum tumor necrosis factor-α（TNF-α）

interleukin-1β（IL-1β） of rats was detected. The growth and distribution of tumors were observed

hematoxylin eosin（HE） staining was used to observe the pathological changes

the expressions of RhoA and ROCK1 proteins in normal colon tissues and colon cancer tissues were detected. RESULTS: The body weight of rats in the normal group increased steadily over time

and the colon tissue structure was normal without inflammatory cell infiltration. Rats in the model group had slow weight gain

red and swollen anus

loose stools

prominent tumor tissues on the colon

abnormal colonic tissue structure

and severe inflammatory cell infiltration. The final body weight of the rats in the low-dose

medium-dose

and high-dose dexmedetomidine group was higher than that in the model group

the intestinal wall erosion and bleeding were reduced to varying degrees

the colon tissue structure was relatively complete compared with the model group

and the degree of inflammatory cell infiltration decreased. Compared with the normal group

the levels of serum TNF-α and IL-1β and the expression of RhoA and ROCK1 proteins of colon cancer tissue in the model group increased significantly（P<0.05）. Compared with the model group

the levels of serum TNF-α and IL-1β

and the expression of RhoA and ROCK1 proteins of colon cancer tissue in the low-dose

medium-dose

and high-dose dexmedetomidine group decreased significantly

with statistically significant differences（P<0.05）. CONCLUSIONS: Dexmedetomidine has a certain therapeutic effect on colon cancer rats

which may be related to its inhibition of RhoA/ROCK1 pathway.