Evaluation of active carbon fibers used in cell biocompatibility and rat cystitis treatment

Escherichia coli is the predominant pathogen in catheter-associated urinary tract infection (CAUTI) and cystitis. CAUTI treated with prophylactic antibiotics induces antibiotic resistance in hospitals and nursing homes. Therefore, we developed a physical method to treat cystitis by using activated carbon (AC) fibers to remove lipopolysaccharide (LPS) from the bladder. An in vitro assay showed that AC had remarkable LPS adsorption capability (20.24 EU per mg AC for 60 min) and good biocompatibility, as revealed by morphological observation through field-emission scanning electron microscopy and MTS assay in SV-HUC-1 cell line. In an in vivo assay in rats, 3 groups were formed: control (pyrogen-free saline), LPS, and AC (n = 10, each group). The LPS and AC groups were pretreated with protamine sulfate (10 mg/mL), and E. coli LPS (5 mg/kg) was administered to induce cystitis. Subsequently, the AC group received 0.4 mg/kg AC suspension. After 24 h, histologic analysis revealed increased urinary bladder weight (edema) and marked increase in vascular congestion and hemorrhage in the LPS group. In contrast, the AC group showed significant reduction in degree of edema, inflammatory cell infiltration, and hemorrhage (p < 0.05). Thus, AC has the potential to act as an auxiliary agent for cystitis amelioration.