Effects of BRL 37344 on spexin immunoreactivity after experimental ischemia/reperfusion injury in rat kidney tissue

Objective: Acute renal failure resulting from renal ischemia/reperfusion (IR) injury is an important clinical problem due to its high mortality rate. In this context, it is of great importance to identify new therapeutic strategies to reduce renal IR injury. Spexin is a novel neuropeptide that has been suggested to have protective effects in many organs, including renal tissue, and has been reported to have potential benefits in oxidative stress-related damage. BRL 37344, on the other hand, is known as a β3-adrenergic receptor agonist, especially for its effects on reducing myocardial IR damage, and stands out as an agent worth investigating for its effects on the kidney. In this study, we aimed to investigate the effects of BRL 37344 on spexin immunoreactivity after experimental IR injury in rat kidney. Materials and Methods: In this study, 35 adult male Sprague Dawley rats aged 8-10 weeks were used. The rats were randomly divided into five groups (n=7). Control Group (Group I) rats were not subjected to any treatment. In the SHAM Group (Group II) rats, the renal pedicles were surgically exposed after general anesthesia, but renal clamping was not performed. BRL 37344 Group (Group III) rats received a single intraperitoneal (i.p.) injection of 5 mcg/kg BRL 37344 after general anesthesia, followed by surgical exposure of the renal pedicles, but no clamp was applied. In Ischemia/Reperfusion (IR) Group (Group IV) rats, ischemia was induced by clamping the bilateral renal artery and vein with hemostasis clips for 30 minutes after general anesthesia. After ischemia, the clips were removed and reperfusion was performed for 45 minutes. IR + BRL 37344 Group (Group V) rats received a single i.p. dose before reperfusion in addition to the IR protocol. 5 mcg/kg BRL 37344 injection before reperfusion. Biochemical analyses were performed by measuring total oxidative stress (TOS), total antioxidant level (TAS) and serum spexin levels. In addition, histopathological findings such as edema, congestion, tubular degeneration, hydropic degeneration and tubular vacuolization were evaluated in kidney tissues from all groups. TUNEL staining was performed as a marker of apoptosis in renal tissues and immunoreactivity of the spexin was evaluated by immunohistochemical staining. The data obtained were compared statistically. viii Results: In biochemical analyses, no significant difference was observed in TAS and TOS levels in the SHAM and BRL groups compared to the control group, whereas TOS levels were significantly increased in the IR group (p=0.001). On the other hand, TOS levels decreased significantly in the IR + BRL group compared to the IR group (p=0.005). A significant decrease was observed in TAS levels in the IR group compared to the control group (p=0.022). However, TAS levels were significantly increased in the IR + BRL group compared to the IR group (p=0.005). There was no statistically significant difference between the control group and the SHAM and BRL groups in terms of serum spexin levels. Serum spexin levels decreased significantly in the IR group compared to the control group (p=0.001). However, in the IR + BRL group, spexin levels increased significantly compared to the IR group (p=0.001). As a result of the statistical evaluation of the scoring made by considering parameters such as edema, congestion, tubular degeneration and tubular vacuolization in histopathological examinations, it was determined that there was a significant increase in the histopathological score in the IR group compared to the control group (p=0.005). However, these findings were significantly decreased in the IR + BRL group compared to the IR group (p=0.035). TUNEL staining showed that the number of TUNEL positive cells, a marker of apoptosis, increased in the IR group compared to the control group (p=0.001), but this increase was significantly decreased in the IR + BRL group (p=0.008). In terms of spectin immunoreactivity, a significant decrease was observed in the IR group compared to the control group (p=0.003). In contrast, immunoreactivity was significantly increased in the IR + BRL group compared to the IR group (p=0.004). Spexin immunoreactivity in the SHAM (p=0.623) and BRL (p=0.960) groups was similar to the Control group. Conclusion: This study demonstrated that BRL 37344 provides significant ameliorative effects in the treatment of ischemia-reperfusion (IR)-induced kidney injury. In our study, BRL 37344 was found to limit the harmful effects on tissue by reducing oxidative stress levels and preserve cellular integrity by suppressing ix apoptosis. It was also observed to increase spexin immunoreactivity, which contributes to the protection of kidney tissue. Spexin is a neuropeptide that attracts attention with its tissue protective potential, especially in pathological conditions associated with oxidative stress and inflammation. Our study showed that the decrease in spexin levels due to IR injury was significantly increased by BRL 37344. In addition, histopathological evaluations revealed that BRL 37344 significantly decreased damage indicators such as edema, tubular degeneration and apoptosis and provided healing effects in kidney tissue. These findings suggest that BRL 37344 can be used as an effective agent in the treatment of IR-induced renal dysfunction and tissue damage, and that the positive effects on the immunoreactivity of the spectin may contribute to these therapeutic mechanisms. Further studies may also investigate the potential benefits of BRL 37344 in other organ systems and long-term effects. Keywords: Ischemia/reperfusion injury, BRL 37344, spexin, rat