Experimental Study Of Evening Primrose Oil Inhibitory Effect On Melamine And Cyanuric Acids Tones In Rats

Objective:Taking gamma-linolenic acid (GLA) and fish oil can significantly decrease the urinary calcium. Evening primrose oil, a rich source of y-linolenic acid, can decrease urinary calcium excretion in both normal and hypercalciuric rats, also can reduce the risk of urinary calcium oxalate stone. However, its application in the prevention of melamine and its analogues stones has not been reported, we use animal experiments to explore its possible mechanism in the prevention of melamine and its analogues stones formation.Method:75adult male SD rats were randomly divided into5groups:group A (normal control), group B, C (stone forming), group D, E (intervention),(n=15). After one week of adaptation, Rats in group A fed with distilled water2g once a day for4weeks, and twice a day for4weeks. Rats in group B,C fed with distilled water2g once a day for4weeks, then melamine(400mg·(kg·d)-1), a mixture of equal melamine and cyanuric acid (60mg·(kg·d)-1) respectively at am,and distilled water2g at pm for4weeks. Rats in group D,E fed with evening primrose oil(containing y-linolenic acid9.2%, linoleic acid75.8%, α-linolenic acid0.2%)2g once a day for4weeks, then melamine(400mg·(kg·d)-1), a mixture of equal melamine and cyanuric acid (60mg·(kg·d)-1) respectively at am, and evening primrose oil2g at pm for4weeks. Nine weeks later,all rats were sacrificed and the renal function,24h blood and urine biochemical indexes, the renal crystallization, pathological changes, Osteopontin expression, were detected.Results:The serum creatinine and blood urea nitrogen in group E were obviously lower(P<0.05), urine creatinine, urine citrate,urine PH increased(P<0.05). statistical difference, there was statistical significance between group E and group A,C.Urolithic rats(group C) were observed more crystals dispositions in all parts of the kidney, especially in cortico-medullary junction, and severe dilation of tubules and massive inflammatory infiltration, and more OPN protein expression than group A and group E. The serum creatinine and blood urea nitrogen in group D were lower, especially of blood urea nitrogen(P<0.05), It was concluded that there was statistic difference between group D and group A,B.Group B were observed no crystals dispositions in the kidney, slight dilation of tubules and few inflammatory infiltration, and there was lower OPN protein expression compared with group A and group D.Conclusion:It is suggested that Evening primrose oil can protect and improve renal function, increase urinary citrate excretion and urinary PH, prevent Melamine crystal formation. It may be valuable for prevention and treatment of Urolithiasis in children taken melamine-contaminated milk powder.