The histopathological and ultrastructural effects of topical application of bacitracin on to the cerebral cortex in rats

Abstract

AIm: Bacitracin is one of the most frequently used agents for the topical irrigation of the cerebral cortex. The aim of this study is to investigate whether bacitracin has histopathological and ultrastructural effects when applied topically to the cerebral cortex. mATErIAl and mEThOds: Twenty-eight rats were randomly assigned to four groups. Except the control group, each rat underwent left frontoparietal craniectomy with dural removal. Then, in the sham group a piece of dry absorbable gelatin sponge was placed over the left hemisphere; in the saline group a gelatin sponge soaked in normal saline; and in the bacitracin group a gelatin sponge soaked in 500 units bacitracin was used. After 48 hours, brain tissues were extracted for histopathological and electron microscopic analyses.rEsulTs: Among the four groups dark stained neurons were found to be statistically higher in number in the bacitracin group compared with the control, sham and saline groups. Electron microscopic evaluation revealed that, in the bacitracin group, almost all cytoplasmic organelles were poorly preserved.CONClusION: Topical application of the bacitracin on to the cerebral cortex caused histopathological and ultrastructural changes in the neural tissue. These changes may be an evidence for the neurotoxic effects of bacitracin.

PEGylated Self-Assembled Nano-Bacitracin A: Probing the Antibacterial Mechanism and Real-Time Tracing of Target Delivery in Vivo

“…All of the copolymers showed no visible antibacterial activities (MICs > 128 μM; see Supporting Information, Table S3). BA solution was effective only against Gram-positive bacteria, and this result correlated well with those of previous studies. − All of the tested PEGylated nano-BAs, except nano-BA 5k , demonstrated strong antibacterial activities compared with those of nano-BA PLGA , and nano-BAs with longer PLGA chains were preferred. It is worth noting that nano-BA 12k even exhibited efficiency against Gram-negative bacteria comparable to that of polymyxin B, a conventional Gram-negative bactericide.…”

“…Two days after infection, the mice were injected with the BA solution, nano-BA PLGA , nano-BA 5k , or nano-BA 12k with an equivalent BA dose (30 mg/kg) via tail vein. At predetermined time points (4,8,12,24,36, and 48 h), the mice were sacrificed, infected thighs were harvested and weighed, and the BA content was quantified by HPLC/MS/MS analysis.…”

Synthesis, construction, and evaluation of self-assembled nano-bacitracin A as an efficient antibacterial agent in vitro and in vivo

“…As shown in Table 3, BA solution showed antibacterial activities against only gram-positive bacteria -a result consistent with previous findings. 6,[23][24][25][26] Nano-BAs (Nano-BA 3K and Nano-BA 5K ) had high effectiveness against both gram-positive and gram-negative bacteria. Their MICs were cell-type dependent and were close to or even below the CMC of the triblock copolymers.…”

Moody microbes or fecal phrenology: what do we know about the microbiota-gut-brain axis?

“…However, caution must be taken when interpreting the results of such studies as the antibiotics themselves may have effects in addition to and unrelated to their antimicrobial actions. Bacitracin, for example, is a protease inhibitor and has been demonstrated to have neurotoxic and/or antinociceptive effects when delivered to the brain [ 65 , 66 ]. Furthermore, minocycline, a synthetic tetracycline antibiotic, has been shown to exert neuroprotective effects and to delay motor alterations, inflammation and apoptosis in various animal models of neurodegenerative diseases and traumatic brain injury [ 67 , 68 ].…”