Effects of Hemp seed soft capsule on colonic ion transport in rats.

AIM

To investigate the effect of Hemp seed soft capsule (HSCC) on colonic ion transport and its related mechanisms in constipation rats.

METHODS

Sprague-Dawley male rats were randomly divided into three groups: normal group, constipation group and HSSC group. Rats in the constipation and HSSC groups were administrated loperamide 3 mg/kg per day orally for 12 d to induce the constipation model. Then, the HSSC group was given HSSC 0.126 g/kg per day by gavage for 7 d. The normal and constipation groups were treated with distilled water. After the treatment, the fecal wet weight and water content were measured. The basal short-circuit current () and resistance were measured by an Ussing Chamber. Besides the drug delivery experiment above, an drug application experiment was also conducted. The accumulative concentrations of HSSC (0.1 mg/mL, 0.5 mg/mL, 1.0 mg/mL, 2.5 mg/mL, 5.0 mg/mL, 10.0 mg/mL and 25.0 mg/mL) were added to the normal isolated colonic mucosa and the was recorded. Further, after the application of either ion (Cl or HCO) substitution, ion channel-related inhibitor (N-phenylanthranilic acid, glybenclamide, 4,4-diisothiocyano-2,2-stilbenedisulfonic acid or bumetanide) or neural pathway inhibitor [tetrodotoxin (TTX), atropine, or hexamethonium], the induced by HSSC was also measured.

RESULTS

In the constipation group, the fecal wet weight and the water content were decreased in comparison with the normal group ( < 0.01). After the treatment with HSSC, the fecal wet weight and the water content in the HSSC group were increased, compared with the constipation group ( < 0.01). In the constipation group, the basal was decreased and resistance was increased, in comparison with the normal group ( < 0.01). After the treatment with HSSC, the basal was increased ( < 0.05) and resistance was decreased ( < 0.01) in the HSSC group compared with the constipation group. In the experiment, beginning with the concentration of 1.0 mg/mL, differences in were found between the experimental mucosa (with HSSC added) and control mucosa. The of experimental mucosa was higher than that of control mucosa under the same concentration (1.0 mg/mL, < 0.05; 2.5-25 mg/mL, < 0.01). After the Cl or HCO removal and pretreated with different inhibitors (cAMP-dependent and Ca-dependent Cl channels, Na-K-2Cl cotransporter (NKCC), Na-HCO cotransporter or Cl/HCO exchanger inhibitor), there were differences between experimental mucosa and control mucosa; the of experimental mucosa was lower than that of control mucosa under the same concentration ( < 0.05). Meanwhile, after pretreatment with neural pathway inhibitor (TTX, atropine, or hexamethonium), there were no differences between experimental mucosa and control mucosa under the same concentration ( > 0.05).

CONCLUSION

HSSC ameliorates constipation by increasing colonic secretion, which is mediated the coaction of cAMP-dependent and Ca-dependent Cl channels, NKCC, Na-HCO cotransporter or Cl/HCO exchanger.