Objective  To investigate the effect of vitamin C (VC) combined with vitamin D₃ (VD₃) on intestinal permeability in guinea pigs with dextran sulfate sodium (DSS)-induced colitis.

  Methods  Twenty-four male Dunkin-Hartley guinea pigs were randomly divided into four groups (6 in each group) according to their weight after one week acclimatization: normal (N) group with 200 international unit (IU)/kg VD₃ + 100 mg/kg VC, model (M) group with 200 IU/kg VD₃ + 100 mg/kg VC, low VC (LC) groupwith, 200 IU/kg VD₃ + 10 mg/kg VC, and high VC (HC) group with 200 IU/kg VD₃ + 200 mg/kg VC. All the pigs were fed with a vitamin D₃- and vitamin C-deficient feed and the corresponding doses of VC and VD₃ were given by gavage for 5 weeks. Then the pigs of the N group were supplied with distilled water and the other 3 groups were supplied with 2% dextran sodium sulfate solution for 4 days. The pigs′ serum 25-hydroxycholecalciferol(25-(OH) D₃) and 1, 25-dihydroxyvitamin D3 (1, 25-(OH)₂D₃) were detected with radioimmunoassay and serum diamine oxidase (DAO), D-lactic acid, and lipopolysaccharide (LPS) were measured with enzyme-linked immunosobent assay (ELISA). Distal colon tissue samples of the pigs were collected and examined with microscope for pathological scaling after paraffin embedding and haematoxylin-eosin (HE) staining.

  Results  The pathological score of the distal colon tissues increased significantly in the pigs of M, LC, and HC groups than that in the pigs of N group (P < 0.05 for all). The serum DAO was 252.02 ± 1.74 U/ml for the pigs of M group, 253.06 ± 2.54 U/ml for LC group, and 253.06 ± 2.54 U/ml for HC group, respectively, significantly higher than that for N group (all P < 0.05); the serum LPS was significantlydecreased to 109.74 ± 13.37 EU/mL for the pigs of LC group and to 111.58 ± 12.49 EU/mL for HC group (both P < 0.05).

  Conclusion  Administration of vitamin C combined with a certain dose of vitamin D₃ could protect intestinal mucosal barrier function in guinea pigs with DSS-induced colitis.