Observation of culture conditions for Trichinella spiralis muscle larvae in vitro.

Objective To observe the development of Trichinella spiralis muscle larvae in vitro in different media.Methods The larvae were inoculated in different media and cultured at 37 ℃ in 5%CO2 for 18 days.The molting time and rate of the cultured larvae were observed,and larval length was measured.Results The time when the larvae cultured in RPMI-1640,RPMI-1640+5% fetal bovine serum(FBS),PBS and saline began to molt was 15,19,23 and 37 h,respectively.Larvae with 1-4 and 1-2 sheath(s) were formed in RPMI-1640 and RPMI-1640 +5% FBS medium.Only a single sheath was observed when larvae were cultured in PBS and saline.The molting rate of larvae cultured in RPMI-1640 medium(77.94%) was significantly higher than that in 3 other kinds of media(39.83%,44.64%,and 8.84%) after culturing for 5 days(Z1640+5%FBS=-2.268,ZPBS=-2.641,Zsaline=-6.826,P0.05).After culturing for 18 days,the molting rates of larvae with 2-4 sheaths cultured in RPMI-1640 medium(25.6%,1.32% and 0.26%) were significantly higher than that in RPMI-1640+5% FBS medium(0.45%,0 and 0)(Z2=-16.111,Z3=-7.991,Z4=-3.885,P0.05).There was no statistically significant difference in the length of larvae cultured in RPMI-1640 and RPMI-1640+5% FBS medium for 1-18 days(t=0.138,P0.05),and the length decreased as the culturing time increased(F1640=54.639,F1640+5%FBS=26.928,P0.05).Conclusion The majority of T.spiralis muscle larvae cultured in RPMI-1640 and RPMI-1640+5% FBS medium were unable to completely shed the old cuticle and develop into adults.