We are pleased that our recent article published in Arthritis Research and Therapy could draw such great interest from the readers. The following is our response to Ma and colleagues' concerns .
In response to the first question, at the beginning of the research we had screened the entire apoptotic pathways using the Rat Apoptosis RT2 Profiler™ PCR Array (SABiosciences, Frederick, MD, USA), and the result (Table 1 in the original paper ) showed that mRNA expression of Bcl-2 family members regulating the intrinsic pathway did not appear to be significantly changed. We therefore subsequently focused on the extrinsic apoptotic pathway based on the screening data. This does not represent negligence of the intrinsic apoptotic pathway.
In response to the second question, there is not enough evidence to support the hypothesis that miRNAs are essential for the apoptotic process in osteoarthritis. Furthermore, it is even rare to see any study that indicates the anti-apoptosis effect of sodium ferulate is mediated by miRNAs. Confirmation of these factors is another scientific issue.
In response to the third question, we appreciate Ma and colleagues pointing out our inaccurate description. A correction has now been published to delete the sentence 'All of these results show that different concentrations of SF [sodium ferulate] from 125 to 1,000 μmol/l have no effect on normal chondrocyte viability' in the first section of Results .
Accordingly, we argue that it is not necessary to conduct the additional investigation on the intrinsic apoptotic pathway and the mechanism involved in miRNAs. This extra work recommended by Ma and colleagues would not enhance the persuasive capability of the conclusion in our paper.
The authors declare that they have no competing interests.
Ma J, Li A, Zhu S, Cao XR, Pei GX: Response to 'TNF/TNFR signal transduction pathway-mediated anti-apoptosis and anti-inflammatory effects of sodium ferulate on IL-1β-induced rat osteoarthritis chondrocytes in vitro'. [http://arthritis-research.com/content/15/3/408] webcite
Qin J, Shang L, Ping A-s, Li J, Li X-j, Yu H, Magdalou J, Chen L-b, Wang H: TNF/TNFR signal transduction pathway-mediated anti-apoptosis and anti-inflammatory effects of sodium ferulate on IL-1β-induced rat osteoarthritis chondrocytes in vitro.
Qin J, Shang L, Ping AS, Li J, Li XJ, Yu H, Magdalou J, Chen LB, Wang H: Correction: TNF/TNFR signal transduction pathway-mediated anti-apoptosis and anti-inflammatory effects of sodium ferulate on IL-1β-induced rat osteoarthritis chondrocytes in vitro.