Maggot debridement therapy (MDT) is a method for the treatment of intractable, infected and necrotic wounds. In MDT, sterile larvae of Lucilia sericata Meigen (Diptera: Calliphoridae) are applied to infected wounds, where they exert antibacterial effects. Once the larvae are placed in the wound, they are no longer germ-free. This study analysed the influence of infected environments on larval antibacterial activities. Sterile larvae were mixed in a test tube containing a bacterial suspension of Staphylococcus aureus or Pseudomonas aeruginosa, transferred to liver puree agar, and incubated at 25 °C for set periods. To collect the larval extracts, the incubated larvae were transferred to a test tube containing phosphate buffered saline (PBS), cut into multiple pieces with scissors, and centrifuged. The supernatant was used to test antibacterial activities. The results showed that infected larvae had better antibacterial capacities than sterile larvae. Antibacterial activities were induced by pretreatment with a single bacterial species, S. aureus or P. aeruginosa, within 24 h and 12 h, respectively, and disappeared after 36 h. The activities were effective against S. aureus, but not against P. aeruginosa. This natural infection model is very similar to the clinical wound context in MDT and will be a powerful tool with which to study the antibacterial activities of L. sericata larvae in MDT.

Artificial diets have been developed for Lucilia sericata (Meigen) blowfly larvae; however, diets for adults have not yet been developed. An adult diet that excludes animal tissues and animal-derived ingredients and promotes not only ovarian development, but also oviposition, would aid in basic research and maggot debridement therapy. We have successfully developed artificial diets that exclude animal tissues and animal-derived ingredients for L. sericata adults. The outcomes of the diets were comparable with those of a beef liver diet in terms of oviposition, adult survival and number of offspring.

A 3-year-old thoroughbred colt presented with canker on its left hind foot. Subsequent development of cottage cheese-like horns and dermatitis disturbed healing, despite the use of miscellaneous orthodox treatment approaches to the lesions. Histological examination revealed exudative and suppurative dermatitis, and proliferatively suppurative epidermitis infected with helically coiled treponemes. Total debridement under general anesthesia led to a temporary improvement, but the ground surface regenerated abnormal epidermis similar to that observed initially after surgery. Maggot debridement therapy (MDT) was attempted, which removed all the abnormal tissue. After MDT, general farriery trimming helped to correct the distorted ground surface, and the horse returned to constant training and eventually raced. This case shows that MDT was successfully used for treatment of an intractable and treponemes-infected canker.

Atrionatriuretic peptide (ANP) is reported to be useful for attenuating myocardial ischemia-reperfusion injury and improving left ventricular function after reperfusion. However, ANP may be either ineffectual or harmful in cases where the myocardium has been chronically hypoxic since birth. This can be a result of the concomitant high levels of cyclic guanosine monophosphate (cGMP) produced within the myocardium. This study aimed to verify the validity of using ANP to improve left ventricular function after myocardial ischemia-reperfusion injury. For this purpose, a cyanotic congenital disease model that was developed using isolated rat hearts was used. Hearts were obtained from Sprague-Dawley rats that were housed from birth until 6 weeks of age either in a hypoxic environment with 13-14% FiO(2) (hypoxic group) or in ambient air (normoxic group). These hearts were subjected to 30min of normothermic global ischemia followed by 30min of reperfusion using the Langendorff technique. Left ventricular functional recovery in hearts administered ANP (0.1µM) into the reperfusion solution was compared with those hearts that were not administered ANP in both hypoxic (without ANP: n=6, with ANP: n=6, with ANP and HS-142-1[an antagonist of ANP]: n=6) and normoxic hearts (without ANP: n =6, with ANP: n=6). In the hypoxic hearts, ANP administration improved the percent recovery of the left ventricular developed pressure (76.3±9.2% without ANP vs. 86.9±6.7% with ANP), maximum first derivative of the left ventricular pressure (82.4±1.1% without ANP vs. 95.8±6.5% with ANP), and heart rate (85.6±4.7% without ANP vs. 96.1±5.2% with ANP) after reperfusion. The improvement and recovery of these cardiac functions were closely related to significantly increased levels of postischemic cGMP release after ANP administration. The effect of ANP was blocked by HS-142-1. The improvements observed in the hypoxic group were similar to those found in the normoxic group. ANP administration during reperfusion improved left ventricular function after myocardial acute global ischemia-reperfusion equally in both the chronically hypoxic and age-matched normoxic groups.

The developmental rate under low temperatures and cold tolerance were investigated in embryos of the blowfly Lucilia sericata. The larvae of this species are now widely used in maggot debridement therapy. Embryonic development was dependent on temperature, with a lower developmental threshold of 9.0 °C. The duration of the egg stage at a rearing temperature of 25 °C was 14 h, and a low temperature of 12.5 °C successfully prolonged this period to 66 h. Embryonic stages differed markedly in their cold tolerance; young embryos were less tolerant to cold than old ones. Late embryonic stages are suitable for cold storage at 5 °C and the storage for 72 h did not decrease the hatching rate by more than 50%. In the mass‐rearing process required for maggot debridement therapy, either of these two simple protocols would be beneficial.