- The objectives of this study were to determine the effects of acupuncture in dairy cows on caruncular matrix metalloproteinase type-2 (MMP2) tissue concentration and enzyme activity at 0, 2, and 4 hours after calving. Immediately after natural calving, a caruncle was obtained from the body of the uterus and flash frozen. Collection was repeated at 2 and 4 hours after calving. Acupuncture was administered to cows (n=6) following each caruncle collection and applied to 6 points reported to relax the cervix and stimulate uterine contractions. Untreated controls (n=9) were kept in a stanchion for 15 minutes without any stimulation. Caruncles were homogenized in buffer and centrifuged. The supernatant was collected and the protein concentration was determined. MMP2 concentrations were calculated using commercial bovine ELISAs. Zymography was performed by electrophoresis on 8% polyacrylamide and 0.6% gelatin. Enzymatic activity was quantified using a digital camera and true 16-bit data capture system. Mean band intensities (indicating enzyme activity) for each molecular mass category between treatment groups and time points were compared using Student’s t-test. The mean value for each time point for each cow was used to calculate the mean ± SEM for each treatment group. MMP2 tissue concentration was lower 2 hours after calving in the control cows (p=0.02) but not in the acupuncture treated cows. Five distinct gelatinases were found in the bovine caruncle at 0, 2, and 4 hours after calving. Enzyme activity of the 49 kDa gelatinase decreased from 0 to 2 hours after calving in control cows (p=0.03) but not in acupuncture treated cows. This gelatinase corresponds to the active form of MMP2. This study provides physiologic evidence for the effects of acupuncture on the bovine reproductive tract and substantiates the use of this treatment in cases of placental retention.
Key Words: cow, gelatin zymography, immunohistochemistry, matrix metalloproteinase type 9, placentome, retained placenta