Background and Aim: Interstitial fibrosis is the final stage of chronic kidney injury, which begins with an inflammatory process. Crude Ganoderma applanatum polysaccharides are known to have anti-inflammatory properties. The potential role of crude G. applanatum polysaccharides in renal fibrosis through pro-inflammatory cytokines needs further investigation. This study aimed to determine the renoprotective effect of crude G. applanatum polysaccharide extract in mice with carbon tetrachloride (CCL₄)-induced early kidney fibrosis.

Materials and Methods: This study was conducted for 4 weeks using 24 male BALB/c mice selected for their metabolic stability. The mice were randomly divided into six groups, including control (CG), model (MG), silymarin group and crude G. applanatum polysaccharide extract groups comprising doses of 25, 50, and 100 mg/kg body weight. After sacrificing the mice, whole blood was analyzed for urea and creatine levels, and kidney tissue was prepared to assess tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), hyaluronic acid (HA), and laminin levels, both using enzyme-linked immunosorbent assay. Kidney histology was determined using hematoxylin and eosin staining, while the extracellular matrix (ECM) components were stained using Masson's trichome staining. The α-smooth muscle actin (α-SMA) concentration was determined using immunohistochemistry. These parameters were measured to determine the effectiveness of the crude G. applanatum polysaccharide extract in preventing interstitial fibrosis.

Results: Administration of crude G. applanatum polysaccharides effectively prevented increases in kidney weight and physiological enzymes, pro-inflammatory cytokines, and ECM production compared with those in the MG, as evidenced by the low levels of urea, creatinine, TNF-α, IL-6, HA, and laminin. Histopathological results also showed that crude G. applanatum polysaccharides prevented the occurrence of inflammatory infiltration, desquamated nuclei, cytoplasm debris, rupture at the brush border, dilatation of the glomeruli space and lumen of the proximal tubule, and necrotic cells compared with the MG. Masson's trichrome staining revealed lower collagen levels in the interstitial tubules of kidney tissue than those in the MG. Immunohistochemical analysis revealed low α-SMA expression in the crude G. applanatum polysaccharides treatment groups than that in the MG.

Conclusion: The crude polysaccharide extract of G. applanatum has a protective effect that prevents the progression of kidney fibrosis in mice.

Keywords: anti-inflammatory, carbon tetrachloride, fibrosis, Ganoderma applanatum, kidney.