Mechanism of Modified Liuwei Dihuangtang in Bone Protection of CKD-MBD Model Rats： An Exploration Based on Klotho-FGF23 Axis / 中国实验方剂学杂志

ABSTRACT

Objective:To observe the effects of modified Liuwei Dihuangtang on serum fibroblast growth factor 23 （FGF23）， full-length intact parathyroid hormone （iPTH）， and 1，25-dihydroxyvitamin D₃［1，25（OH）₂D₃］ levels and Klotho and FGF23 protein expression in renal and bone tissues of rats exposed to high phosphorus combined with adenine， so as to explore the mechanism of modified Liuwei Dihuangtang against renal osteopathy. Method:One hundred and thirty healthy adult SD rats were randomly divided into five groups， namely normal group（<italic>n</italic>=10），high phosphorus group（<italic>n</italic>=30），model group（<italic>n</italic>=30），modified Liuwei Dihuangtang group（<italic>n</italic>=30） ， and calcitriol group（<italic>n</italic>=30），and rats in each group were further classified based on three time points， namely 8，10， and 12 weeks. Rats in the normal group were fed with normal diet， the ones in the high phosphorus group with high phosphorus diet， and those in the other groups with adenine and high phosphorus diet for inducing renal osteopathy. Rats in the normal group，high phosphorus group， and model group were intragastrically administered with distilled water （10 mL·kg^-1·d^-1），the ones in the modified Liuwei Dihuangtang group with modified Liuwei Dihuangtang （2.556 g·kg^-1·d^-1） ， and those in the calcitriol group with calcitriol （0.09 μg·kg^-1·d^-1）. Result:Compared with the normal group and high phosphorus group at the weeks of 8，10 and 12，the model group displayed significantly elevated blood urea nitrogen（BUN），serum creatinine（SCr），serum phosphorus，iPTH，FGF23，renal interstitial fibrosis score， and FGF23 expression in renal and bone tissues， but lowered serum calcium and 1，25（OH）₂D₃ and Klotho protein expression in renal and bone tissues（<italic>P</italic><0.05 ，<italic>P</italic><0.01）. Compared with the model group at the weeks of 8，10 and 12， the modified Liuwei Dihuangtang and calcitriol both significantly decreased the serum BUN，SCr，serum phosphorus，iPTH， FGF23， tubulointerstitial semi-quantitative score， and FGF23 expression in renal and bone tissues， while increased the serum calcium，1，25（OH）₂D₃， and Klotho protein expression in renal and bone tissues （<italic>P</italic><0.05，<italic>P</italic><0.01）. There was no significant difference in the above-mentioned indexes between the modified Liuwei Dihuangtang group and the calcitriol group at the same time point. Conclusion:Klotho-FGF23 axis is probably involved in renal osteopathy. The modified Liuwei Dihuangtang effectively improves renal function，alleviates pathological changes in renal and bone tissues，and regulates calcium and phosphorus metabolism to protect the bone， which is related to its regulation of Klotho-FGF23 axis.