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SUMMARY:BALANCING CELL COMPATIBILITY AND ANTIMICROBIAL EFFECTS OF 470 NM I
 N AN INFECTED HYPERGLYCAEMIC WOUND CELL MODEL
DTSTART;VALUE=DATE-TIME:20260325T132000Z
DTEND;VALUE=DATE-TIME:20260325T134000Z
DTSTAMP;VALUE=DATE-TIME:20260426T115552Z
UID:indico-contribution-10312@events.saip.org.za
DESCRIPTION:Speakers: Francis Obeng Brenya (University of Johannesburg)\nF
 .O. Brenya1 and N.N. Houreld1*\n1Laser Research Centre\, University of Joh
 annesburg\, Johannesburg\, South Africa \nE-mail: nhoureld@uj.ac.za*\nAnti
 microbial photobiomodulation (aPBM) with blue light (400-490 nm) is a prom
 ising non-invasive adjunct therapy for infected chronic diabetic foot ulce
 rs (DFUs). Still\, its fluence-dependent effects on human dermal fibroblas
 ts remain poorly defined. This study investigated the fluence-dependent re
 sponse of fibroblasts (BJ-5ta) cultured under three conditions: normal (N)
 \, normal wounded (NW)\, and hyperglycaemic wounded (HW)\, with or without
  bacterial infection.  BJ-5ta fibroblasts (6 × 10⁵ cells/mL) were co-cu
 ltured with Staphylococcus aureus\, Streptococcus pyogenes\, or Pseudomona
 s aeruginosa (1.5×10³ CFU/mL) and irradiated with 470 nm blue laser ligh
 t (power output 800 mW\; power density 88 mW/cm²) at 5\, 10\, 30\, 55\, 1
 00\, or 120 J/cm². After 24 hours\, fibroblast viability\, migration\, mo
 rphology\, and bacterial survival were evaluated. Low fluences (5-10 J/c
 m²) maintained fibroblast viability at ≥90% across all uninfected model
 s. In contrast\, higher fluences (30-120 J/cm²) caused a marked\, dose-
 dependent decrease in fibroblast viability\, with the lowest values observ
 ed at 120 J/cm² in both normal and hyperglycaemic wounded models. Infec
 tion with S. aureus\, S. pyogenes\, and P. aeruginosa  increased cytotoxic
 ity\, with each species showing the greatest reduction in fibroblast viabi
 lity at ≥55 J/cm². Fibroblast migration in the uninfected normal woun
 ded model decreased progressively at fluences over 30 J/cm²\, dropping 
 to 22-30% at 120 J/cm². In infected normal wounded models\, migration d
 eclined in a species-dependent manner\, with minimum values of 22-30% for 
 S. aureus\, 37-48% for S. pyogenes\, and 21-27% for P. aeruginosa at 120
  J/cm². CFU counts were significantly reduced at 5-10 J/cm² for all 
 species. At 30-120 J/cm²\, S. aureus and P. aeruginosa were unaffected\
 , whereas S. pyogenes exhibited a sustained\, significant decrease in bact
 erial load. These results suggest a potential therapeutic window at 5-30
  J/cm²\, within which fibroblast function is largely preserved while ba
 cterial burden is reduced\, supporting dose-optimised application of 470
  nm aPBM in vitro.\n\nhttps://events.saip.org.za/event/272/contributions
 /10312/
LOCATION:
URL:https://events.saip.org.za/event/272/contributions/10312/
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