Morphine Hydrochloride On The Larvae Of Chrysomya Megacephala In Nature And Its Forensic Significance

Objective: To study the growth and development of Chrysomyamegacephal reared in muscles containing morphine hydrochloride in natureand the changes of experimental index to explore the regularity of change withtime, and accumulate a large amount of data on forensic toxicologicalentomology from Shijiazhuang city to provide some reference for inferring thePostmortem interval (PMI) after the death of the larvae of Chrysomyamegacephal.Materials and Methods: Adult Chrysomya megacephal were collectedfrom the outdoors. The experiment was done with offsprings of the thirdgeneration. Four domestic rabbits were prepared. The first one was used as acontrol and the other three were given morphine via ear vein according to thedifferent dosages. All the rabbits were sacrificed by hitting the head quickly30minters later. The muscles from the four rabbits were take down and stored.They were marked with M0、M1、M2and M3. The Adult flies were rearedsuccessively in biochemical culture boxes under the temperature of28℃.Thehumidity, photoperiod and food supply were kept unchanged during the entirestudy. Induced spawning with fresh lean pork. Form then on, eggs were placedonto each group of test muscle tissues to initiate the test colonies.When larvae were laid,10of them were randomly sampled from eachgroup at12h intervals until eclosion. The larvae were fixed in boiling waterand then preserved in70%alcohol mixed with glycerine.1Measurements of lengths and weighsThe samples were taken out from the preserved solution and the liquid ofsurface was blotted up by the filter paper. Measure and record the body lengthand weight and length and weight.2Preparation and observation of experimental specimen The samples were taken out from the preserved solution and the liquid ofsurface was blotted up by the filter paper. Stick some holes on the abdomensof specimen with a pin, then fill them with10%KOH to corrod their innards.24hours later, press the larvae gently until they excreted the corroded tissues.Washed several times in clean water, it was taken apart that the section ofscolex subsequent the2nd section thoracic part and after the8th section underthe stereomicroscope with anatomical scissors and scalpel. The specimenswere dehydrated with alcohol from30%to100%gradually. After beingtransparent with dimethylbenzene, the specimens were observed andphotographed. Finally the indexes including areas of different parts of anteriorspiracle, posterior spiracle and cephalopharyngeal skeleton had been given bydigital image processing equipment.Use analysis of variance (ANOVA) when made statistical analysisdifferent indexes. Finally the data were statistically curved with AdobeIllustrato.Results:1With the increase of the concentration of morphinehydrochloride, the length and weight of larval also increased. The higher theconcentration of morphine hydrochloride and the longer the average length ofthe larval. The average weight is the same as the average length. The drugincreased the maximum body length and weight, the time required is the same.The change of the pupa is not clear.2On M1, M2and M3group, the persistent growth of the area and theaverage optical density of larval anterior spiracle has been stopped until thelate age of3rd, and in M0group, the trend of growth increased gradually allthe time.3All of the four groups, the persistent growth of the area of larvalposterior spiracle has not been stopped, and the trend of the average opticaldensity has been stopped until the late age of3rd.4Morphological characteristics of cephalopharyngeal skeleton4.1With the larvae growing, the color of each part of the larvaecephalopharyngeal skeleton, anterior spiracle, posterior spiracle became deeper than ever. The degree and range of chitinazation in cephalopharyngealskeleton increased in accordance with the development.4.2The variation trend of the sclerotized area, the area and the averageoptical density of the larvae cephalopharyngeal skeleton increased graduallyuntil the age of3rd.4.3Morphine hydrochloride increases the maximum about pharynx bonearea, pharynx bone ossification area, pharynx bones average light density; butit did not change the time required.5The larval were reared in muscles containing morphine hydrochloridein a natural environment that the average temperature was22℃-23℃, it cost12d to finish the life history. From eggs to half pupate need4.5d, from pupateto half eclosion need7.5d.Conclusions:1The length and weight of larval increased with time untilthe age of3rd, then, body length is constant and the weight loss. Morphinehydrochloride increases the maximum but it did not change the time required.2The change of the pupa is not significantly. With the increase of theconcentration of morphine hydrochloride， the length and weight of pupa alsoincreased.3The persistent growth of the area and the average optical density oflarval anterior spiracle increased gradually all the time. The posterior spiracleis as well.4Under the same drug concentration, with the larvae growing, the colorof each part of the larvae cephalopharyngeal skeleton, anterior spiracle,posterior spiracle became deeper than ever. The degree and range ofchitinazation in cephalopharyngeal skeleton increased in accordance with thedevelopment. Larval mouth bone can be found in the3rd age.5The variation trend of the sclerotized area, the area and the averageoptical density of the larvae cephalopharyngeal skeleton increased graduallyuntil the age of3rd. Morphine hydrochloride increases the maximum.6The time required to breeding larva in a natural environment is shorterthan indoor environment with constant temperature. Especially reducing the time from eggs to adult. Morphine hydrochloride did not change the timerequired.