[The expression of glial cell line-derived neutrophil factor and its effect on colonic transit function in slow transit constipation rats].

OBJECTIVE: To investigate the distribution and expression of glial cell line-derived neutrophil factor(GDNF)in colon of slow transit constipation (STC) rats and the effect of exogenous GDNF on colon transit. METHODS: Forty-eight SD rats were divided randomly into controlled group and model group. The models were established by gastric irrigation of rhubarb for 3.5 months. The control group received normal saline. The models were successfully established and then the rats were divided randomly into four groups. They were a normal group, GDNF group, STC model group and a STC models plus GDNF group. Half of the rats in model and control group were administrated with exogenous GDNF intravenously for one week. The expression of GDNF and GDNF-mRNA in colon was detected with immunohistochemistry and RT-PCR. The colon transmit speed was measured with Chinese ink driving test. RESULTS: The colon transmit of the STC model group, the normal group, the STC models plus GDNF group and GDNF group were (60.00 +/- 5.62)%, (74.44 +/- 2.19)%, (74.67 +/- 7.07)% and (88.54 +/- 3.22)%. There was significant difference between the normal group and the STC model group (P < 0.01) as well as the STC models plus GDNF group and the STC model group (P < 0.01). The expression of GDNF with reverse transcriptase PCR in the STC model group, the normal group and the STC models plus GDNF group was 1.38, 2.29 and 2.21 respectively, with significant difference between the STC models and the normal group (P = 0.01) and between the STC models and the STC models plus GDNF group (P = 0.017). However, there was no significant difference between the normal group and the STC models plus GDNF group (P > 0.05). CONCLUSIONS: The down regulation of GDNF in colon may play an important role in pathogenesis of STC. Exogenous GDNF may improve the colon motor function by up-regulation of GDNF.