Kupffer cells (KCs) play a pivotal role in the progression of metabolic-associated steatohepatitis (MASH). This study evaluated the impact of short-term KC depletion induced by gadolinium chloride (GdCl₃) in a rat model of MASH. The intervention with GdCl₃ effectively reduced KC markers CD68 and Clec4f, together with pro-inflammatory cytokines (IL-1β, TNFα, NOS2), without affecting anti-inflammatory markers (IL-10, MRC1). Histologically, GdCl₃ reduced hepatocyte ballooning and NAS despite persistent steatosis. KC depletion was associated with decreased oxidative stress markers (TBARS, 3-nitrotyrosine) and antioxidant enzyme activity (SOD, catalase). Additionally, markers of endoplasmic reticulum stress (ATF4, GRP78, CHOP, P58^IPK) and apoptosis (BAX/BCL2 ratio, cleaved caspase-3) were diminished. Despite these improvements, GdCl₃ had no effect on lipid or glucose metabolism in the liver, associated with persistent elevation of PTP1B expression induced by SRD intake. KC depletion, however, increased FGF21 expression. GdCl₃ treatment improved systemic insulin sensitivity and reduced fasting glucose and NEFA serum levels. In white adipose tissue, the treatment decreased adipocyte size, restored insulin signaling, and inhibited lipolysis (ATGL expression) without altering macrophage infiltration (IBA) or thermogenic protein levels (UCP1) in SRD rats. These findings suggest that KC depletion modulates liver-to-adipose tissue crosstalk, potentially through FGF21 signaling, contributing to improved systemic metabolic homeostasis of SRD animals.

The sustained consumption of sucrose-rich diet has deleterious effects on the adrenal cortex, impairing its steroidogenic capacity. As hemin treatment has been shown to exert cytoprotective effects (e.g., by heme oxygenase 1 induction), our main goal was to analyze the adrenocortical function in rats treated with diet and hemin. Male Wistar rats fed standard chow and 30% sucrose in the drinking water (SRD) for 12 weeks ad libitum were injected with hemin for the last 2 weeks of treatment. mRNA and proteins were analyzed by real-time polymerase chain reaction, western blot or immunofluorescence, and corticosterone levels were assessed by radioimmunoassay. A decrease in lipid peroxides and an increase in the activity of catalase were detected in the SRD + H group. Moreover, pro-inflammatory markers (TNF-α, IL1β, CXCL10, NOS2, NALP3 and MCP1), IBA1+/ED1+ cells and NFκβ activation were still elevated in tissues from SRD + H-treated rats, whereas an increase in markers of macrophages with the M2-phenotype (ARG1, MRC1 and TGFβ) was also shown. Activation of ER stress in SRD-treated rats (CHOP, XBP1s and P58IPK) and the induction of apoptosis (TUNEL and the BAX/BCL2 mRNA ratio) were also attenuated by hemin. Finally, ACTH-stimulated glucocorticoid production, significantly decreased in SRD-treated rats, was upregulated by hemin. The consumption of SRD involves exposure of tissues to a higher metabolic load that could generate oxidative stress and a pro-inflammatory state. Deleterious consequences of these processes could account for the significant decrease in the ACTH-induced corticosterone output from the gland. By correcting these effects, hemin treatment was able to restore the hormone-induced adrenocortical response.