Anti-Inflammatory and Anti-Oxidant Effects of Chlorella vulgaris in an Experimental Acute Peritonitis Model

Objectives: Acute peritonitis remains a critical condition with high mortality rates, further complicated by the rising antibiotic resistance. This study aimed to investigate the therapeutic potential of Chlorella vulgaris (CHL), both alone and in combination with standard antibiotic therapy (SFT), in a rat model of cecal ligation and puncture (CLP)-induced peritonitis. Methods: Seventy (70) male Wistar albino rats were divided into seven groups (n = 10): Control, Peritonitis Control, Low-dose CHL (CHL I) (150 mg/kg), High-dose CHL (CHL II) (300 mg/kg), the standard first-line therapy group (SFT) (Ceftriaxone + Metronidazole), SFT + CHL I, and SFT + CHL II. Following CLP-induced peritonitis, treatments were administered for 7 days. Peritoneal tissues were evaluated histopathologically and immunohistochemically for TNF-α, IL-1β, IL-10, and iNOS expression. Total Antioxidant Status (TAS) and Total Oxidant Stress (TOS) were measured to assess the oxidative stress. Results: Histopathological analysis showed that CLP-induced severe inflammatory damage was significantly reduced in all treatment groups, with the most prominent recovery observed in the SFT + CHL II group. CHL treatment led to a significant decrease in pro-inflammatory markers (TNF-α, IL-1β, iNOS) compared to the peritonitis control group (PC) (p < 0.05). Furthermore, CHL administration significantly improved the oxidative balance by increasing TAS and reducing TOS levels. Conclusions: Chlorella vulgaris exhibits significant anti-inflammatory, antioxidant, and immunomodulatory properties in experimental peritonitis. When used as an adjunct to standard antibiotic therapy, high-dose CHL provides synergistic effects that contribute to limiting tissue damage and controlling systemic inflammation. These findings suggest that CHL may be a promising supportive agent in the clinical management of acute peritonitis.