Objective To observe the effects and its possible mechanism of Heidihuang Pills（ 黑地黄丸） on the microinflammation of renal tissue in rats with renal fibrosis. Methods A total of 50 Wistar rats were randomly divided into a normal group

a model group and a Heidihuang Pills high

middle and low dose groups

with 10 rats in each group. Except the normal group

the rats were performed 5/6 nephrectomy to establish a renal fibrosis model.From the day after surgery

rats in the high

middle and low dose groups of Heidihuang Pills were given intragastric administration of drug solution respectively containing 2

1

0. 5 g/ml crude drug with 10 ml/kg

and the model group as well as the normal group were given the same volume of normal saline

once a day

continuous administration for60 days. The levels of serum creatinine（ Cr）

blood urea nitrogen（ BUN） and high-sensitivity C-reactive protein（ hs-CRP） were measured in each group. The pathological changes of renal tissue were observed by HE staining. Immunohistochemistry and western blot were used to detect the expression of Toll-like receptor 2（ TLR2）

nuclear factorκB（ NF-κB） and myeloid differentiation factor 88（ Myd88） in renal tissues. Immunohistochemistry was used to detect the expression of inflammatory factor including tumor necrosis factor（ TNF-α）

interleukin 6（ IL-6） in renal tissue. Results Compared with the normal group

the levels of serum Cr

BUN and hs-CRP in the model group were significantly increased

and the expressions of TLR2

NF-κB

Myd88

TNF-α and IL-6 in renal tissues were also increased（ P < 0. 05）. Compared with the model group

the serum levels of Cr

BUN and hs-CRP in the high

middle and low dose of Heidihuang Pills groups were significantly decreased

and the expressions of TLR2

NF-κB

Myd88

TNF-α and IL-6 in renal tissues were also decreased（ P < 0. 05）. There was no significant difference in the indexes of the high

middle and low dose of Heidihuang Pills groups（ P > 0. 05）. HE staining showed that the glomerular deformation

tubulointerstitial widening and inflammatory cell infiltration in the model group

while renal interstitial edema

glomerular sclerosis

and tubular atrophy and inflammatory cell infiltration in the high

middle and low dose of Heidihuang Pills groups were alleviated compared with the model group

and the difference among different dose groups was not significant. Conclusion Heidihuang Pills can significantly improve the microinflammation of renal tissue in renal fibrosis rats

and its mechanism may be related to the regulation of TLR2/NF-κB/Myd88 pathway in renal tissue.