Celastrol Ameliorates Renal Injury in Spontaneously Hypertensive Rats by Activating the Nrf2/Ho-1 Signaling Pathway to Alleviate Oxidative Stress

Celastrol (CSL), a natural triterpenoid extracted from Tripterygium wilfordii, demonstrates a wide range of biological activities. In this study, we explored whether CSL alleviates kidney damage in spontaneously hypertensive rats (SHRs) through the modulation of the Nrf2/Ho-1 pathway, a crucial target in renal injury models. A total of 40 male SHRs, aged 6–8 weeks, were randomly allocated to four groups: the control group (CON, serving as the healthy control), the spontaneously hypertensive rat group (SHR), the SHR group treated with low-dose CSL (L-CSL + SHR, 0.5 mg/kg/d), and the SHR group treated with high-dose CSL (H-CSL + SHR, 1 mg/kg/d). All drugs were formulated using physiological saline as the solvent and administered via intraperitoneal injection. The control group received an equivalent volume of physiological saline via intraperitoneal injection, and all groups underwent continuous daily administration for 6 weeks. The results indicated that, in comparison with the control group, the serum levels of angiotensin, angiotensin-converting enzyme, and aldosterone in the SHR group were relatively high, and CSL treatment further downregulated these indices. Simultaneously, CSL downregulated pro-inflammatory factors (tumor necrosis factor-α and interleukin-1β) and upregulated interleukin-6. Regarding renal function-related indicators, CSL reduced malondialdehyde levels and enhanced the activities of antioxidant enzymes, such as superoxide dismutase, glutathione peroxidase, and catalase. Moreover, CSL inhibited the overexpression of Keap1. Significantly, the mRNA levels of Nrf2, Nqo1, and Ho-1 in the CSL-treated groups were notably higher than those in the SHR group. These findings suggest that CSL mitigates renal pathological damage in SHR by activating the Nrf2/Ho-1 pathway, offering a potential therapeutic approach for hypertension-induced renal injury.