The objective of this study was to investigate if delivering multiple doses of N-acetylcysteine (NAC) post-surgery in addition to pre-incisional administration significantly impacts the wound healing process in a rat model. Full-thickness skin incisions were carried out on the dorsum of 24 Sprague-Dawley rats in six locations. Fifteen minutes prior to the incision, half of the sites were treated with a control solution, with the wounds on the contralateral side treated with solutions containing 0.015%, 0.03% and 0.045% of NAC. In the case of the NAC treated group, further injections were given every 8 h for three days. On days 3, 7, 14 and 60 post-op, rats were sacrificed to gather material for the histological analysis, which included histomorphometry, collagen fiber organization analysis, immunohistochemistry and Abramov scale scoring. It was determined that scars treated with 0.015% NAC had significantly lower reepithelization than the control at day 60 post-op (p = 0.0018). Scars treated with 0.045% NAC had a significantly lower collagen fiber variance compared to 0.015% NAC at day 14 post-op (p = 0.02 and p = 0.04) and a lower mean scar width than the control at day 60 post-op (p = 0.0354 and p = 0.0224). No significant differences in the recruitment of immune cells and histological parameters were found. The results point to a limited efficacy of multiple NAC injections post-surgery in wound healing.

Surgical flaps are rudimentary tools in reconstructive surgery, especially following extensive solid tumour resections. They cover skin and soft tissue defects but are prone to ischaemia and necrosis. Since their primary aim is reconstruction, they rarely exhibit a therapeutic activity against the treated disease. Attempts have been made to develop a new therapeutic strategy—biologic brachytherapy, which uses genetically engineered surgical flaps as a drug delivery vehicle, allowing the flap tissue to act as a “biologic pump”. This systematic review summarizes the preclinical evidence on using genetically modified surgical flaps. A literature search was conducted in PubMed, EMBASE, Scopus and Web of Science. The initial literature search yielded 714 papers, and, eventually, seventy-seven studies were included in qualitative analysis. The results show that genetic enhancement of flaps has been used as a local or systemic therapy for numerous disease models. Frequently, it has been used to increase flap survival and limit ischaemia or promote flap survival in a non-ischemic context, with some studies focusing on optimizing the technique of such gene therapy. The results show that genetically modified flaps can be successfully used in a variety of contexts, but we need more studies to implement this research into specific clinical scenarios.

Background: Breast cancer (BC) is highly heterogeneous, with varying molecular characteristics, such as reliance on autophagy. Autophagy is a critical cellular degradation process that helps cells survive under stress, but its regulation can be influenced by altered microRNA (miRNA) expression. Studying miRNA changes during starvation-induced autophagy in both mammary epithelial cells and BC cells could reveal potential molecular therapy targets. Methods: Rat mammary gland healthy epithelial and cancer cells were subjected to starvation, and differences in proliferation, migration, invasion, autophagy, and expression of autophagy-associated miRNAs were determined. Afterward, we assessed the effects of miR-218-5p modulation on the aforementioned processes. Results: Starvation-induced autophagy reduced the proliferation of all cells and increased the invasive and migratory capacity of cancer cells (p ≤ 0.05). We identified a miRNA signature related to starvation, comprising twenty-seven miRNAs. One miRNA had a significantly elevated baseline expression, while another six, including miR-218-5p, had a significantly lower basal expression in cancer cells compared to healthy cells (p ≤ 0.05). However, starvation caused significant miRNA expression changes, with miR-218-5p being upregulated specifically in cancer cells (p = 0.20–0.01). Functional studies on the role of miR-218-5p show that its inhibition decreases migration and leads to autophagosome accumulation. The study of miR-218-5p molecular targets has shown that its inhibition of sorting nexin 18 (SNX18) may act as an important regulator of the starvation-induced response in cancer cells. Conclusions: The baseline expression of miRNA related to starvation and autophagy differs between rat mammary gland cancer and healthy cells. The response to starvation also varies between cancer cells and normal cells. Starvation induces BC-specific miRNA dysregulation, affecting particularly miR-218-5p, which acts via SNX18, promoting the cancer cells’ survival.

Background: Adipose-derived stem cells (ADSCs) are readily harvestable, tumour-homing cells that have been engineered as vehicles for antitumour agents. TNF-related apoptosis-inducing ligand (TRAIL) selectively triggers apoptosis in many cancer cells through death receptors DR4/DR5, while sparing most healthy cells. To date, only human TRAIL has been studied in such delivery systems; a fully homologous rat model (rat TRAIL delivered by rat ADSC) has not been tested, despite being essential for future syngeneic in vivo studies. Methods: In this pilot, exploratory study, we lentivirally transduced rat ADSC (rADSC) to express myc-tagged rat TRAIL, characterized the expression of TRAIL-pathway components in rADSC and three rat mammary carcinoma cell lines (RBA, HH-16.cl.4, SHZ-88) at the mRNA and protein levels, and assessed the antitumour effect of rTRAIL-rADSC using recombinant TRAIL dose–response, supernatant transfer, direct co-culture, and nine-day insert co-culture assays. Results: rADSCs were successfully transduced and produced cell-associated rat TRAIL (66.2 pg per 50,000 cells versus 4.4–5.7 pg in controls; p < 0.05); this ELISA measures total cell-associated (intracellular plus membrane-anchored) TRAIL rather than soluble TRAIL. rADSC expressed markedly higher levels of the decoy molecule osteoprotegerin and of DR4/DR5 than the cancer cells. Two of three cancer lines (RBA, HH-16.cl.4) were susceptible to rat TRAIL, and rTRAIL-rADSC reduced their growth and increased the proportion of dead cells, with morphological features compatible with both apoptosis and necrosis, most markedly in HH-16.cl.4; the effect was separable from the empty-vector control in HH-16.cl.4 but not in RBA. Conclusions: In this pilot study, homologous rat TRAIL delivered by rADSC is feasible and increases cell death in TRAIL-susceptible rat mammary cancer cells, but the effect is moderate at most, contact-dependent, and in one of two susceptible lines not attributable to TRAIL itself. These findings define both the potential and the limitations of a fully translational rat model of TRAIL-based biologic brachytherapy and provide a foundation for future in vivo studies.