Effects of immunosuppressive drugs on gastrointestinal transit of rats: effects of tacrolimus, cyclosporine, and prednisone.

Triple immunosuppressive therapy after organ transplantation may cause several gastrointestinal disturbances. It is difficult to identify which drug causes more complications, requiring an appropriate animal model. The aim was to compare the gastrointestinal transit in immunosuppressed rats under triple immunosuppressive therapy. Male rats were immunosuppressed by gavage during 14 days with tacrolimus (n = 10), cyclosporine (n = 12), and prednisone (n = 9). Animals received a magnetic pellet before (control) and after treatment that was monitored at predetermined intervals by AC biosusceptometry, a noninvasive and radiation-free technique. The following parameters were measured: creatinine serum, mean time of gastric emptying (MGET), mean time to reach cecum (MCAT), and mean transit time through small bowel (MSBTT). The differences were analyzed by ANOVA (Tukey). Our results showed that MGET of animals treated with prednisone, cyclosporine, and tacrolimus were reduced compared with control subjects (P < .03, P < .009, and P < .002, respectively). There was no difference in MCAT, whereas MSBTT was longer for tacrolimus and prednisone compared with control subjects (P < .004 and P < .004, respectively). Also, prednisone and tacrolimus presented a reduced MGET (P < .05 and P < .01, respectively) compared with cyclosporine. Our data showed a low serum creatinine level and no difference among groups regarding renal function. In summary, cyclosporine has less effect on the gastrointestinal transit; however, all of these drugs should be carefully prescribed to prevent gastrointestinal symptoms and improve quality of life after transplantation.