Ciprofloxacin modulates cytokine/chemokine profile in serum, improves bone marrow repopulation, and limits apoptosis and autophagy in ileum after whole body ionizing irradiation combined with skin-wound trauma.

Radiation combined injury (CI) is a radiation injury (RI) combined with other types of injury, which generally leads to greater mortality than RI alone. A spectrum of specific, time-dependent pathophysiological changes is associated with CI. Of these changes, the massive release of pro-inflammatory cytokines, severe hematopoietic and gastrointestinal losses and bacterial sepsis are important treatment targets to improve survival. Ciprofloxacin (CIP) is known to have immunomodulatory effect besides the antimicrobial activity. The present study reports that CIP ameliorated pathophysiological changes unique to CI that later led to major mortality. B6D2F1/J mice received CI on day 0, by RI followed by wound trauma, and were treated with CIP (90 mg/kg p.o., q.d. within 2 h after CI through day 10). At day 10, CIP treatment not only significantly reduced pro-inflammatory cytokine and chemokine concentrations, including interleukin-6 (IL-6) and KC (i.e., IL-8 in human), but it also enhanced IL-3 production compared to vehicle-treated controls. Mice treated with CIP displayed a greater repopulation of bone marrow cells. CIP also limited CI-induced apoptosis and autophagy in ileal villi, systemic bacterial infection, and IgA production. CIP treatment led to LD(0/10) compared to LD(20/10) for vehicle-treated group after CI. Given the multiple beneficial activities of CIP shown in our experiments, CIP may prove to be a useful therapeutic drug for CI

CIP accelerated bone marrow recovery after CI.

<p>On day 10 after CI, femurs were collected from surviving mice and prepared for hematoxylin-eosin staining on paraffin sections. Representative histopathology photos are shown. n = 4−5 per group. CI: combined injury; CIP: ciprofloxacin; Veh: vehicle.</p

CIP inhibited the CI-induced increase in caspase-3 after CI.

<p>On day 1 after CI, ileal samples were collected from surviving mice and total cell lysates were prepared for detection of caspase-3 activity. Data is presented by the levels equivalent to <i>p</i>-nitroaniline (<i>p</i>NA). n = 6 per group; *<i>p</i><0.05 vs. sham-Veh, sham-CIP, and CI+CIP. CI: combined injury; CIP: ciprofloxacin; Veh: vehicle.</p

CIP improved survival after irradiation combined with skin-wound trauma (CI).

<p>Mice received 9.75 Gy ⁶⁰Co γ-photon radiation followed within 1 h by 15% TBSA skin wound (CI). Mice were given CIP (90 mg/kg <i>p.o. q.d.</i>) or vehicle for 11 days starting day 0≤2 h after CI. Experiment was repeated to achieve statistical significance. n = 10 per group, *<i>p</i><0.05 vs. CI+CIP. CI: combined injury; CIP: ciprofloxacin; Veh: vehicle.</p

CIP inhibited the CI-induced increase in IgA expression after CI.

<p>On day 10 after CI, ileal samples were collected from surviving mice and prepared for immunofluorescent staining on paraffin sections. IgA expression was detected (red) with counterstaining with nucleus (blue). Representative pictures are shown with their fluorescence intensities for red signals (bottom). n = 4−5 per group. CI: combined injury; CIP: ciprofloxacin; Veh: vehicle.</p

CIP did not ameliorate CI-induced depletion of white blood cells (WBC) and platelets.

<p>On day 10 after CI, whole blood was collected from surviving mice and tested for numbers of WBCs and platelets. n = 4−5 per group; *<i>p</i><0.05 vs. sham-Veh, sham-CIP. CI: combined injury; CIP: ciprofloxacin; Veh: vehicle.</p

CIP inhibited ileum injury after CI.

<p>On day 10 after CI, ileal samples were collected from surviving mice and prepared for hematoxylin-eosin staining on paraffin sections. (A) Representative histopathology photos are shown, (B) An average mucosal injury grade was calculated as a damage index of 5 villa in 3 representative mice (<i>n</i> = 15) per group. *<i>p</i><0.05 vs. sham-Veh, sham-CIP, and CI+CIP, and (C) Crypt depth was measured. <i>n</i> = 4−5 per group. CI: combined injury; CIP: ciprofloxacin; Veh: vehicle.</p