OBJECTIVETo explore roles of mRNA and protein expressions of organic anion transporting polypeptide (oatp2b1) of rats with high fat diet and overstrain induced Pi deficiency syndrome in the transporting of damp turbidity.

METHODSTotally 24 SD rats were randomly divided into three groups, i.e., the normal group, the overstrain group, and the high fat diet group, 8 in each group. After successful modeling, one piece of tissues such as spleen, kidney, liver, lung, stomach, small intestine, and large intestine was taken from each rat. Rats of the overstrain group were bonded by specially made bondage cylinder, 3 h each time on odd days, and forced to swim in cold water (10 +/- 1) degrees C for 7 min on even days alternatively for twelve weeks. Rats in the model group and the normal group were fed with standard routine granular forage for 12 weeks. Rats in the high fat diet group were fed with high fat forage for twelve weeks. All rats drank and ate freely. The mRNA and protein expressions of oatp2b1 were detected in the seven tissues using RT-PCR and Western blot.

RESULTSThe mRNA expression of oatp2b1 in liver and kidney tissues of rats in the high fat diet group was higher when compared with that of the normal group and the overstrain group (P < 0.01, P < 0.05). The oatp2b1 mRNA expression in the normal group was sequenced from high to low as liver > lung > spleen > larger intestine > small intestine > kidney > stomach. The oatp2b1 mRNA expression in the overstrain group was sequenced from high to low as liver > lung > larger intestine > spleen > kidney > stomach > small intestine. The oatp2b1 mRNA expression in the high fat diet group was sequenced from high to low as liver > lung > spleen > small intestine > kidney > larger intestine > stomach. The oatp2b1 protein expression in the lung tissue was sequenced from high to low as the overstrain group > the normal group > the high fat diet group (P > 0.05). The oatp2b1 protein expression in the spleen tissue was sequenced from high to low as the high fat diet group > the normal group > the overstrain group (P > 0.05). The oatp2b1 protein expression in the kidney tissue was sequenced from high to low as the normal group > the overstrain group > the high fat diet group (P > 0.05). The oatp2b1 protein expression in the liver tissue was sequenced from high to low as the normal group > the high fat diet group > the overstrain group (P > 0.05). Of them, the oatp2b1 protein expressed extremely less in the stomach, large intestine, and small intestine. The oatp2b1 protein expression in the normal group was sequenced from high to low as lung >spleen > liver, kidney > stomach, larger intestine, and small intestine. The oatp2b1 protein expression in the overstrain group was sequenced from high to low as lung > spleen > kidney > liver > stomach, larger intestine, and small intestine. The oatp2b1 protein expression in the high fat diet group was sequenced from high to low as spleen > lung > kidney > liver > stomach, larger intestine, and small intestine. However, there was no statistical significance among the three groups by pair-wise comparison (P > 0.05).

CONCLUSIONSKidney and liver might play important roles in the transportation and transformation of damp under the state of Pi deficiency syndrome. Oatp2b1 may be one of the material bases involved in the transportation and transformation of damp turbidity. Pi's function of governing transportation and transformation of damp might not only include the functions of the gastrointestinal tract, but also include partial liver and kidney functions.